Dustin Johnson has resigned from the PGA Tour in order to play in the Saudi-backed LIV Golf Invitational Series.

The two-time major winner is one of the biggest names to sign up for the new league, and his loss represents a significant blow to the PGA Tour, of which he had been a member since 2007.

Johnson's decision to turn his back on the PGA Tour means he will be unable to complete in the Ryder Cup.

"It's too early to speak on what the consequences will be, but as of right now, I resigned my membership from PGA Tour, I'm going to play here for now, that's the plan," he told reporters.

"But what the consequence are going to be, I obviously can't comment on how the Tour is going to handle it.

"The majors, again I can't answer for the majors, but hopefully they'll allow us to play. Obviously I'm exempt for the majors, so I plan on playing there unless I hear otherwise."

Adding on the Ryder Cup, he said: "The Ryder Cup is unbelievable and has meant a lot to me, but ultimately I decided this was best for me and my family.

"All things are subject to change, and hopefully at some point it will change and I will get a chance to do that again."

Phil Mickelson has confirmed he will play in the first event of the controversial LIV Golf Invitational Series, but he still intends to feature at the upcoming majors this year.

Dustin Johnson headlined the entrant list for the opening event at Centurion Club near London, which starts on Thursday, but Mickelson was an initial surprise omission from the entry list for the Saudi Arabia-funded competition.

Sergio Garcia, Louis Oosthuizen and Lee Westwood are also among the high-profile names set to feature at the three-day event that will have 12 teams and 48 players.

Mickelson was met with widespread condemnation after criticising the PGA Tour earlier this year, for which he apologised and vowed to take a step back from the game – even missing the defence of his US PGA Championship last month.

His comments on LIV Golf were also met with significant backlash after he said Saudi Arabia has "a horrible record on human rights", but added he was willing to commit to the league as it was "a once-in-a-lifetime opportunity to reshape how the PGA Tour operates".

But Mickelson, who once again reiterated his apologies for his earlier comments, announced on Monday that he will indeed play at the inaugural LIV Golf event.

"I am ready to come back to play the game I love but after 32 years this new path is a fresh start, one that is exciting for me at this stage of my career and is clearly transformative, not just for myself, but ideally for the game and my peers," the American said in a statement. 

"I also love the progressive format and think it will be exciting for fans. Just as importantly, it will provide balance, allowing me to focus on a healthier approach to life on and off the course.

"I am incredibly grateful for what this game and the PGA Tour has given me. I would like to think that I have given back as well but now I am excited about this new opportunity."

Mickelson opted to not defend his PGA Championship this year amid the furore, but the 51-year-old plans to return to compete at the majors alongside his LIV Golf involvement.

"I am thrilled to begin with LIV Golf and I appreciate everyone involved. I also intend to play the majors," he added.

"I fully realise and respect some may disagree with this decision and have strong opinions and I emphasise with that. I have a renewed spirit and excitement for the game.

"I am incredibly grateful for the support of my fans, partners, and peers and I hope in time, those sentiments, relationships and support continue."

Greg Norman, chief executive and commissioner of LIV Golf, added in a statement reported by Sky Sports: "Phil Mickelson is unequivocally one of the greatest golfers of this generation.

"His contributions to the sport and connection to fans around the globe cannot be overstated and we are grateful to have him.

"He strengthens an exciting field for London where we're proud to launch a new era for golf."

Billy Horschel secured victory at the Memorial Tournament on Sunday, shooting an even-par 72 to finish four strokes ahead of Aaron Wise.

Horschel had a healthy buffer at the start of play on Sunday with a five-shot lead and kept it relatively steady, but had to come up with some big shots on the back nine to take the win.

After a bogey on the sixth, the 35-year-old got back to even with a birdie on the par-three 10th.

A bogey on the 12th took him back to one-over, yet a massive put on the par-five 15th for eagle gave Horschel a commanding lead.

It effectively shut the door on Wise, who had also birdied on 15, before he closed out the round with a bogey for a one-under 71.

It was Horschel's seventh tournament win on the PGA Tour, but his first with his family present. Greeted by them and tournament founder Jack Nicklaus after the win, Horschel spoke of the added significance of this triumph.

"It's special, it truly is," Horschel said after his round. "Jack's a legend of the game and to win his event, you've seen the guys who have won this event, just legends in their own right, it's pretty special.

"We joke about it in the family but my wife and my kids have never been to any of my victories. My parents have, and so, having a five-shot lead knowing that this was mine to sort of go out and win or lose, and having them here, I really wanted to win."

Horschel moved into the FedEx Cup's top 10 with the win, just 19 points behind Jon Rahm in ninth.

Excluding the 2021 WGC Match Play, defeating Scottie Scheffler in the final, this win is his first on the PGA Tour in a regular four-round format since the 2018 Zurich Classic.

Coming into Sunday with that five-stroke lead, Horschel was determined to maintain rather than extend that margin.

"I've watched Tiger play enough, and I wasn't around when Jack was playing in his heyday, but you knew he was unbelievable at course management," he said.

"He knew how to plot his way around a golf course and learn from those two, and understand, when you have a lead, you don't have to do anything special. You've just got to make sure you don't give any shots back.

"I did give some back and I was a little upset about it, but we just put the ball on the green, two-putting, trying not to do anything special and if I had to do something special, then I was ready for it. That eagle on 15 was huge."

After months of claim, counter-claim and controversy, the LIV Golf Invitational Series turns its focus to actual golf on Thursday.

The first event of a series previously known as the 'Super Golf League' gets under way at the Centurion Club, near London, next week.

A lucrative breakaway from the PGA Tour and DP World Tour, there will be plenty of interest in how LIV Golf fares – even if it is a largely unpopular venture.

Regardless of its wider reputation, though, the money of Saudi Arabia's Public Investment Fund (PIF) has still attracted some of the sport's best players.

So, what is the deal with LIV Golf? How does it work? Who will be playing? And why has it caused such uproar?

Stats Perform attempts to answer the myriad questions around this contentious competition.

What is LIV Golf?

A Saudi-backed rival to the PGA Tour has been rumoured for years, taking on various names before finally launching as the LIV Golf Invitational Series.

Greg Norman, a two-time Open champion and LIV Golf's CEO, has described this as the arrival of "free agency" in golf, with leading players skipping PGA Tour events to play in the new series.

That is exactly what the PGA Tour sought to avoid when it vowed to ban any players who joined a rival league, although that promise has not yet come to pass.

"Our mission is to modernise and supercharge the game of professional golf through expanded opportunities for both players and fans alike," reads LIV Golf's website, adding its aim to provide "a cutting-edge entertainment product".

That does not only mean a new series and new events, but also a new format...

How does it work?

Gone is the long-established structure of 72 holes across four days with the field cut after two rounds.

Regular season LIV Golf events will last only 54 holes and three days, with no cuts, meaning – organisers point out – there is no danger of eye-catching names being absent for the end of the tournament.

There are also shotgun starts, "ensuring a faster and more exciting pace of play", and smaller fields with only 48 players.

This may all be unfamiliar, but it is at least straightforward. The other changes are a little more complex.

Players will be pursuing individual glory, as at any other golf tournament, but there are also team prizes on offer, with each field broken up into 12 four-man teams.

At every event, there will be an individual winner – the traditional victor with the lowest 54-hole score – and a triumphant team, whose score will be calculated using their best two scores over the first two rounds and their best three from the third.

The first seven events of the season – four in the United States and one each in England, Thailand and Saudi Arabia – will provide a seasonal individual champion, while the year's most successful team are then identified at a further match-play knock-out tournament.

Who's playing?

With a number of big names publicly opposing the breakaway, Rory McIlroy referred to the then Super Golf League as the "not-so-Super League" back in February.

But LIV Golf claims to have received 170 applications and has been able to recruit some superstar talent – namely Dustin Johnson, whose agent said it was "in his and his family's best interest to pursue it".

"Dustin has never had an issue with the PGA Tour and is grateful for all it has given him," David Winkle added. "But in the end, [he] felt this was too compelling to pass up."

It remains to be seen how regularly Johnson will appear in the series, given the field is set to change for every event. He is on board for the London opener, though, alongside Sergio Garcia.

With the four-man teams – who will have their own logos, colours and names – to be tweaked at each tournament, captains will draft players to join them. Unlike at the Ryder Cup, these captains are also active players.

The opening London draft is set for Tuesday, but Phil Mickelson – the most notable and controversial potential LIV Golf star – will not be involved.

Given his previous interest, Mickelson is surely likely to appear at some stage, but he has not played for several months since his comments in relation to the tournament and its funding prompted an apology.

Why's it so controversial?

Any rebel league that threatened the PGA Tour was unlikely to be globally popular, but Saudi Arabia's influence has contributed significantly to the backlash.

The country's human rights record is of major concern, along with its role in the war in Yemen, so ventures such as these – and the acquisition of Premier League club Newcastle United – by its PIF are widely cited as examples of sportswashing.

Norman has suggested Saudi Arabia is "making a cultural change".

While he described the murder of journalist Jamal Khashoggi at the Saudi consulate in Istanbul in 2018 as "reprehensible", the LIV Golf chief added: "Look, we've all made mistakes, and you just want to learn from those mistakes and how you can correct them going forward."

Norman was speaking last month, by which point Mickelson's own discussion of Khashoggi's death had done a great deal of harm to the league's reputation.

The six-time major champion acknowledged Saudi Arabia's "horrible record on human rights" but added he was willing to commit to LIV Golf as it was "a once-in-a-lifetime opportunity to reshape how the PGA Tour operates".

Mickelson made those comments in November last year, although they were reported earlier this year just as the series sought to launch.

Norman said the saga "definitely created negative momentum against us" and revealed "everybody got the jitters", causing some players to back out.

Billy Horschel shot a blistering seven-under 65 on Saturday to secure a five-stroke lead heading into the final round of the Memorial Tournament.

Horschel shot another bogey-free round on Saturday to extend his streak to 44 consecutive holes, with his last coming on the 10th hole in the first round.

One year after Jon Rahm built a six-stroke lead coming into the Sunday at the Memorial, before having to withdraw due to a positive Covid-19 test, Horschel will have a chance to see off the field with a healthy buffer.

After chipping in for birdie on the opening hole, Horschel played incisively from there as the course firmed, zeroing in on the pin and not leaving himself with much work on the greens at Muirfield Village.

The 35-year-old will be going for his seventh tournament win on the PGA Tour, with his last victory coming at the 2021 WGC Match Play, defeating Scottie Scheffler in the final.

World number three Cameron Smith commenced with a one-stroke lead on Saturday but started slowly with bogeys from the bunker on the opening two holes.

He recovered from another bogey to open the back nine to finish on even par for the round, remaining on eight-under for the tournament.

The Australian is tied for second with Aaron Wise, who steadied after a fast start on the front nine to score a three-under 68 on Saturday.

A three-way tie for third between Daniel Berger, Francesco Molinari and Jhonattan Vegas sits a further stroke back.

Meanwhile, defending champion Patrick Cantlay sits on six-under along with another four players.

Kevin Na has announced his resignation from the PGA Tour ahead of his participation in the LIV Golf Invitational Series.

Na, who is a five-time winner on the PGA Tour, posted on social media on Saturday his reasons for resigning, suggesting it was due to the Tour's attitude towards players competing in rival events.

A Saudi-backed rival to the PGA Tour had been rumoured for years before the launching of LIV Golf was recently confirmed.

Greg Norman, a two-time Open champion and LIV Golf's CEO, described it as the arrival of "free agency" in golf, with leading players skipping PGA Tour events to play in the new series.

However, the Tour has previously suggested it would ban players who joined the breakaway.

Na, who is the world number 33, was among 13 players from the PGA Tour listed as part of the field for the first LIV Golf event in London next week, along with the likes of Dustin Johnson, Lee Westwood and Sergio Garcia.

Na posted on Twitter: "For 19 years I have played on the PGA Tour and loved every minute of it. I appreciate the platform the Tour has provided me to play the game I love and for the opportunities that come with it.

"Recent developments in the professional golf world have given me a chance to reconsider my options. I would like the freedom to play wherever I want and exercising my right as a free agent gives me that opportunity.

"However, to remain a PGA Tour player, I must give up my right to make these choices about my career. If I exercise my right to choose where and when I play golf, then I cannot remain a PGA Tour player without facing disciplinary proceedings and legal action from the PGA Tour.

"I am sad to share that I have chosen to resign from the PGA Tour. This has not been an easy decision and not one taken lightly. I hope the current policies change and I'll be able to play on the PGA Tour again.

"I am thrilled to begin the next chapter in my career, starting next week at the inaugural LIV Invitational Series event in London. I hope you'll continue to support me."

The 38-year-old's last Tour win came in January 2021 at the Sony Open in Hawaii.

Cameron Smith continued his strong start to the Memorial Tournament on Friday, sitting alone atop the leaderboard on eight under after being one of three players to shoot under 70 on back-to-back days.

The Australian was in a six-way tie for the lead after round one, and pushed on well his second time around, finishing with just one bogey – on the sixth hole – which was sandwiched by birdies on the fifth and seventh.

Smith then birdied the par-five 11th, and the par-three 12th, showing his impressive touch over long and short distances, but where he really made his money was around the greens.

According to Data Golf, Smith had negative strokes-gained off the tee and with his approach shots in round two, but was second overall in strokes-gained around the greens (plus 3.55), trailing only Beau Hossler (plus 4.25). They gapped the field, with nobody else gaining more than plus 2.83 in that shot category.

Sitting one stroke off the lead is American Denny McCarthy and South Korea's Lee Kyoung-hoon, while one stroke further back at six under are round one's joint-leaders Davis Riley, Cameron Young and Luke List, along with Jhonattan Vegas and Billy Horschel.

McCarthy and Vegas joined Smith as the only players to shoot sub-70 in the opening two rounds.

Rory McIlroy headlines the group at five under in a tie for ninth, along with Francesco Molinari, still well within striking distance heading into the weekend.

A strong international group is at four under, including Canada's Mackenzie Hughes, Chile's Joaquin Niemann and South Korea's Im Sung-jae, and they are one stroke ahead of Ireland's Shane Lowry, Mexico's Abraham Ancer and American Will Zalatoris.

Jon Rahm and Corey Conners will still feel like they have a chance at two under, Max Homa and Xander Schauffele finished well inside the cut-line at one under, and Jordan Spieth shot a disappointing 74 on Friday to take an even par score into the weekend.

England's Aaron Rai – who was number one in strokes-gained off the tee on Friday – along with Australian Adam Scott finished right on the cut-line, making it through at two over, but Matt Fitzpatrick (three over) and Collin Morikawa (four over) were not so lucky.

World number three Cameron Smith headlines a six-way tie atop the Memorial Tournament leaderboard after Thursday's first round at Muirfield Village.

Smith is joined by American trio Luke List, Cameron Young and Davis Riley, as well as Canada's Mackenzie Hughes and South Korea's Lee Kyoung-hoon.

It is the largest leading group after the first round in tournament history, but they all got to their five-under 67 in different ways. 

Young finished the day second in average driving distance (316.8 yards), behind only Jon Rahm, while Lee, Hughes and Smith finished top-six in putts-per-green-in-regulation.

List was the only member of the leading group to finish with less than two bogeys, and Riley played an all-round game; top-15 in driving distance while being dialled in with his putter down the back-nine, going five-under from the 11th hole to the 17th.

US PGA Championship runner-up Will Zalatoris is part of the three-man group one stroke off the lead, while Max Homa and Canada's Corey Conners are in the logjam at three under.

A star-studded group finished with a two-under 70, including Rory McIlroy, Jordan Spieth, Xander Schauffele and Im Sung-jae, while Chile's Joaquin Neimann is with Collin Morikawa and Jason Day at one under.

Patrick Cantlay and Rahm were even-par, Mito Pereira will need a solid second round to make the cut after a one-over finish, and Hideki Matsuyama was handed his first career disqualification for using a wood with paint on its face – deemed illegal. He was three over at the time of the incident.

English golfer Eddie Pepperell claims stars who sign up for the LIV Golf Invitational Series are making it obvious "what money means to you".

Former world top-50 star Pepperell says many players are taking "a big risk" by aligning themselves with the series that is being funded by Saudi Arabia's Public Investment Fund.

Former U.S. Open and Masters champion Dustin Johnson, 37, is among the 42 confirmed entrants for the first event, which will be held at Centurion Club near London from June 9-11.

Sergio Garcia, Kevin Na, Louis Oosthuizen, Ian Poulter, Charl Schwartzel, Graeme McDowell and Lee Westwood are also set to feature in a tournament that will have 12 teams and 48 players.

There have been claims of the event being an attempt at sportswashing, and while Pepperell did not level that accusation, he suggested a lust for money had to be the prime motivation for players who have gone against the wishes of the PGA Tour and European Tour by agreeing to take part.

"From a ROI [return on investment] perspective, the field for the first LIV event is awful," Pepperell wrote on Twitter. "Obviously they're banking on that changing over time. You have to wonder how long they'll keep pouring that amount of money into this if that change doesn't come quickly.

"Plus, deteriorating financial conditions across the world may have an impact. Nobody will be impervious to what we're seeing and what we'll continue to see economically into the next 18 months.

"The players who have signed up should be upfront and honest about their reasons to do so. And it has to be the money. There's nothing wrong with chasing money or higher salaries, people do it across all industries.

"It's somewhat understandable from the older guys… But to those under 35/40 who have signed up, you have taken a big risk. And it shows to the rest of us (peers included) how little commitment you have to your respective Tours (who have done a lot for you), and ultimately what money means to you."

The inaugural tournament clashes with the Canadian Open on the PGA Tour, an event at which Johnson is a previous winner.

Rory McIlroy described the Canada event and this week's Memorial Tournament as "proper golf tournaments" on Wednesday, as he reflected on the LIV Series line-up.

"I certainly don't think the field is anything to jump up and down about," McIlroy said of the Centurion Club tournament.

Northern Irishman McIlroy has tempered his comments on the LIV Series in recent months, having previously been robust in his opposition.

He understands its appeal to some, but has been quite clear he will not be taking part.

"Some guys are in a position where they are not guaranteed a job next year. It's hard to stay in the top 125, especially when you're in your 40s and maybe don't hit the ball as far as you've used to. As we've seen, it's a young man's game nowadays," McIlroy said.

"So if another entity comes along and says, 'we'll guarantee you this amount for three years', plus you're playing for a ton more prize money, you're playing fewer events and you can spend more time with your family it's very appealing to some of those guys that are in that position."

Phil Mickelson had long been linked with the LIV Series, but the 51-year-old has not played since apologising for comments made about the Saudi Arabia regime and has not been included on next week's start list. The American said in February he was taking a break from golf and did not defend his US PGA Championship last month.

Dustin Johnson is among the 42 confirmed entrants for the first event of the controversial LIV Golf Invitational Series but Phil Mickelson's name was not among the participants for the Saudi-funded competition.

Two-time major winner Johnson is the highest-profile name in three-day event, which will be held at Centurion Club near London from June 9-11.

Sergio Garcia, Kevin Na, Louis Oosthuizen, Ian Poulter, Charl Schwartzel, Graeme McDowell and Lee Westwood are also set to feature in a tournament that will have 12 teams and 48 players.

Johnson's name is perhaps the most surprising, with the former world number one having gone back-and-forth over his participation and issued a statement back in February pledging his future to the PGA Tour.

On Tuesday, his agent David Winkle released a statement quoted by ESPN that read: "Dustin has been contemplating the opportunity off-and-on for the past couple of years.

"Ultimately, he decided it was in his and his family's best interest to pursue it. Dustin has never had an issue with the PGA Tour and is grateful for all it has given him, but in the end, felt this was too compelling to pass up."

Mickelson had long been linked with the event, but the 51-year-old has not played since apologising for comments made about the Saudi Arabia regime. The American said in February he was taking a break from golf and did not defend his US PGA Championship last month.

The series has courted plenty of controversy due to the fact it is being funded by Saudi Arabia's Public Investment Fund, leading to claims of sportswashing.

The inaugural tournament clashes with the Canadian Open on the PGA Tour, an event of which Johnson is a previous winner.

Sam Burns drained a putt from off the green to win the Charles Schwab Challenge in a playoff against world number one Scottie Scheffler.

Despite making no birdies on Sunday, Scheffler was in contention all day after entering the day in the outright lead, but had to battle with the difficult conditions later in the day to post a 72.

Burns was in much better touch, and had the benefit of getting his 18 holes out of the way earlier before the wind picked up, notching a 65 for the round of the day. 

He was one shot back from a four-way tie at 10 under when he finished his tournament at nine under, and he had to wait two hours to find out – first if the field would come back to him – and then if Scheffler could hold on for the playoff.

Scheffler needed to save a number of tough pars down the back nine, including out of the bunker on the 18th hole to force the playoff, which he did by sinking a clutch five-footer.

In the playoff, after a pair of solid drives, Scheffler found the green a long way from the hole, while Burns put his approach just off the back of the putting surface. Approaching three hours since his last putt, Burns drained an incredible tournament-winner, with Scheffler not able to match him from distance.

Speaking to the media after securing the win, Burns said it was a hard-fought result.

"I think, just with the conditions today, and how tough it was playing, I'm just so proud of the way we hung in there," he said.

"I just played such a good round of golf today, and [caddie] Travis [Perkins] did a good job of keeping us in it, especially after hitting a foul ball at 12 which killed our momentum. Hitting that putt – that's just icing on the cake."

It is 11 years since Burns attended Colonial Country Club in person to witness David Toms win the Crowne Plaza Invitational, and he said it is hard to believe he is a champion at the same course.

"I don't know if I would've believed you – I remember that week like it was yesterday," he said.

"To finish it off here, and have [Toms'] family here… to add my name on that list now is really cool."

Scheffler's playing partner Brendon Todd finished one stroke outside the playoff, alone in third at eight under, while American trio Tony Finau, Davis Riley and Scott Stallings collected top-five finishes, tied for fourth at seven under. Finau and Burns were the only two players to shoot 67 or better in the final two rounds as the conditions worsened throughout the weekend.

A strong group rounded out the top-10, with pre-tournament favourite Jordan Spieth and US PGA Championship main character Mito Pereira headlining the five-man bunching in a tie for seventh at five under,

Spieth, Riley and Im Sung-jae – who was part of the logjam at three under – were the only three players to shoot 70 or better in all four rounds.

Norway's Victor Hovland was one of two players to finish at two under, while New Zealand's Danny Lee tied Burns for the round of the day, with his Sunday 65 bringing him to one under for the tournament.

Harold Varner III was part of the four-way tie for the lead at 10 under through 11 holes, but went triple-bogey, double-bogey, triple-bogey over his next three holes to plunge down the leaderboard and finish at even par.

Talor Gooch and Webb Simpson joined him at even par, Tommy Fleetwood finished at one over, and Collin Morikawa never shot worse than 71, but never shot better than 70 to finish two over.

Scottie Scheffler leads the Charles Schwab Challenge by two strokes coming into the final round, shooting a two-under 68 in Saturday's third round.

The world number one sits at 11-under coming into the final 18 holes at Colonial, after facing tricky conditions with intense heat and heavy wind gusts.

After posting bogey-free rounds on Thursday and Friday, Scheffler almost made it three rounds in a row but three-putted the par-four 17th for bogey.

He bounced right back with a long birdie putt on the 18th to close out the round on two-under, leading Brendon Todd and Scott Stallings on nine-under.

After missing the cut last weekend at the US PGA Championship, his first cut since his season start in October, the Masters champion could win his fifth PGA Tour title on Sunday.

Those five wins would come from a phenomenal 10 starts, after taking out the Phoenix Open at TPC Scottsdale in February, and would emulate Tom Watson's 1980 feat of five wins before the start of June.

Harold Varner III is in the running for his maiden PGA Tour victory, sitting a further stroke back from Todd and Stallings on eight-under after three rounds, also shooting a two-under 68 on Saturday.

John Huh, Cam Davis, Chris Kirk and Patrick Reed share a four-way tie for fourth on seven-under.

Also shooting a third-round score of 68 was Mito Pereira, finishing strong with three birdies over the closing five holes, including a long 15-metre putt to secure a birdie on the 18th.

Pereira is coming off his dramatic collapse on the final hole at the PGA Championship last weekend, missing the playoff between Justin Thomas and Will Zalatoris.

Both Thomas and Zalatoris have gone on from that performance at Southern Hills to miss the cut this weekend in Fort Worth.

World number one Scottie Scheffler remained in a tie for the lead after his second consecutive bogey-free round at the Charles Schwab Challenge, going one stroke better than his Thursday 66 to sit at nine under.

Scheffler's 65 was one shot off the round of the day, and he did it with back-to-back birdies on holes one and two, before also making gains at 10, 12 and 17 down the back nine.

Fellow round one leader Beau Hossler matched Scheffler again – but after two eagles on par-fours in his first round, he did it in much more traditional fashion this time around, also going bogey-free with five birdies.

Joining that pair atop the leaderboard was Scott Stallings, one of two players to shoot Friday's best score of 64, along with New Zealand's Danny Lee, who improved to sit six off the lead after a 73 on Thursday.

Speaking to Golf Channel after stepping off the 18th green, Scheffler said improvements he has made this season are paying off after traditionally struggling at Colonial Country Club.

"I've worked really hard, just creating a lot of different shots for myself," he said.

"This golf course is a lot about the approach play, and at first it didn't suit my eye, but I've really changed and improved my iron play and created a lot of different shots for myself, and it looks like the hard work is paying off here.

"I think I like it when the conditions are really hard, I'd rather it be very difficult than very easy.

"I feel like it's one of those things where if you're playing really good golf you can kind of extend yourself, so I'm excited for the challenges this weekend."

Patrick Reed sat one stroke back from the lead, alone at eight under after his second 66 of the week, with fellow Americans Pat Perez and Chris Kirk rounding out the top five at seven under.

Next came a five-man group at six under consisting of Americans Max McGreevy, Harold Varner III and Davis Riley, with Australian Cam Davis and Norway's Viktor Hovland.

Pre-tournament favourite Jordan Spieth, Webb Simpson and John Huh stood at five under, while Mito Pereira headlined the logjam at four under, still in the mix after his capitulation at the US PGA Championship last weekend.

Max Homa finished three strokes inside the cut line at two under, while Tony Finau and Rickie Fowler were at one under, and Im Sung-jae was one inside the line at even par.

Collin Morikawa and Talor Gooch made the weekend on the number, finishing at one over, while the US PGA Championship playoff pairing of Will Zalatoris and Justin Thomas were both at three over, out of the hunt this time.

World number one Scottie Scheffler was part of an eight-man group atop the leaderboard after the first round of the Charles Schwab Challenge, played at Colonial Country Club in Texas.

Scheffler, who shot a bogey-free 66 despite only hitting 50 per cent of the fairways in regulation, was joined by fellow Americans Harold Varner III, Chris Kirk, Beau Hossler, Patrick Reed and Webb Simpson, as well as Canadian Nick Taylor and Australian Cam Davis.

Hossler produced the most notable round, with two eagles – both coming on par-fours – in his last four holes to fly up the leaderboard.

One shot off the lead were a group including Davis Riley and Kevin Na, while pre-tournament favourite Jordan Spieth was back at one under, tied with Victor Hovland and Max Homa.

Spieth, who is from Texas, has an impeccable record at Colonial, with seven top-10 finishes – including three runners-up and a win – from nine starts on the PGA Tour.

Speaking to the media after finishing his round, Spieth said he is battling his putter at the moment but that he is confident things will turn in his favour.

"I think I'm typically more comfortable with reads here, although today here was totally different, I misread a number of putts today," he said.

"But I stroked it beautifully, I just felt great about the way I putted, I just didn't get much to go.

"Those are the kind of rounds where you can either look at it negatively, or you can say at it like 'hey, that lid is going to come off one of these times, and all of a sudden they're all going to pour in'.

"It's done that for me [previously] at Colonial, so I think that's the attitude I'm going to take."

At even par were a strong international group including Chile's US PGA Championship main character Mito Pereira, Colombia's Sebastian Munoz, England's Ian Poulter, American Collin Morikawa and the South Korean duo of Lee Kyoung-hoon and Im Sung-jae.

PGA Championship winner Justin Thomas was at one over, while his playoff opponent last week Will Zalatoris was a shot further back at two over.

Rory McIlroy reflected on the US PGA Championship as "one that got away" after he failed to capitalise on a great start at Southern Hills.

McIlroy led the second major of the year after carding a five-under 65 in his first round last Thursday.

That proved to be a false dawn, as the Northern Irishman followed that up with a 71 in his second round and went in the wrong direction on moving day when he shot a 74.

McIlroy finished with a 68 to take eighth place in Tulsa, where Justin Thomas beat Will Zalatoris in a play-off to take the title.

It is eight years since McIlroy won the last of his four majors and he knows he missed a golden opportunity in Oklahoma.

"Regrets? Yeah I regret I didn't take advantage of the benign conditions on Friday afternoon," McIlroy said in a conference call to promote the new GolfNow Compete App.

"I regret the big numbers I made on the par threes on Saturday. The fact that I just needed to play the last 13 holes in one-under par to make a play-off on Sunday, and I didn't.

"So, yeah, I definitely feel like it was one that got away. But, again, I have to take the positives – and the fact that eighth place in a major is absolutely the worst I feel I could’ve finished last week."

The world number eight, runner-up in The Masters last month, is pleased with the progress he has made over the last year.

"The first two majors of last year, I missed the cut at Augusta and I finished like 50th at the PGA," he said.

"I just have to stay as patient as possible. I know that if I keep playing the golf that I'm playing the chances are going to present themselves and I'm going to give myself a few more chances this year, not just to win majors but to win golf tournaments in general."

McIlroy has not spoken to Dr Bob Rotella about his performance at the US PGA, but says his mental coach has been in touch.

"He sent me a nice text on Sunday night," he said.

"There's a lot to be positive about where my golf game is now compared to where it was last year, it's miles ahead of that. I feel like the consistency is back in my golf game that really hasn't been there.

"I feel like this year is very similar to 2019, when I had one of my best years ever and won four times, and I was PGA Tour Player of the Year."

McIlroy will play in the Memorial, the RBC Canadian Open, the Travelers and the U.S. Open. He will then miss the Irish Open and play in the JP McManus Pro-Am prior to The Open at St Andrews, which starts on July 10.