Australian batsman Travis Head has been ruled out of the fourth Ashes Test and returning a positive test for Covid-19.

Cricket Australia confirmed that the 28-year-old is asymptomatic and will not fly with the squad to Sydney on Friday for the fourth Ashes Test due to start at the SCG on January 5.

The remainder of the Australian squad, their families and the team's support staff have undergone PCR and RAT tests on Friday and are still planning to travel to Sydney on Friday.

A Cricket Australia spokesperson said: “As part of our testing procedures, we are PCR testing players, their families and our support staff daily. Unfortunately, Travis returned a positive Covid-19 result earlier today. Thankfully, he is asymptomatic at this stage. We anticipate that he will be available to play in the fifth men’s Ashes Test in Hobart.

“We are grateful to our exceptional medical staff for all the work they have done throughout this series and we will continue to work with and support the players, their families and staff from both teams.”

Mitchell Marsh, Nic Maddinson and Josh Inglis have joined the Australian squad as additional cover as a precautionary measure, although Usman Khawaja appears most likely to replace Head in the XI.

On Friday, there was a huge jump in confirmed Covid-19 cases in Sydney, were the fourth Test will be played, with 21,151 infections diagnosed up from 12,226 on Thursday.

The Boxing Day Test earlier this week was jeopardized after positive cases within the England camp, while Third Test match referee David Boon tested positive on Thursday.

Australia captain Pat Cummins missed the second Test in Adelaide after being a close contact of a confirmed Covid-19 case.

Head becomes the first player to miss a Test in the Ashes series due to testing positive as Covid-19 closes in on the series.

Travis Head was delighted to see Joe Root dismissed with the final ball of day four in Adelaide, while Australia's stand-in vice-captain expects Nathan Lyon to dominate day five of the second Ashes Test.

Root's 24 on Sunday may have seen him overtake Alastair Cook (4,844) to become England's top run-scorer as Test captain, but the current skipper had little to celebrate barring yet another personal landmark in a fantastic 2021 for the Yorkshireman.

The tourists started positively, dismissing nightwatchman Michael Neser (3), Marcus Harris (23) and Steve Smith (6) in quickfire fashion to leave the hosts 55-4.

However, Marnus Labuschagne (51) and Head (51) fought back, before Cameron Green (33 not out) and Mitchell Starc (19) guided Australia to their declaration total of 230-9, setting England a mammoth 468 to win.

Rory Burns (34) and Dawid Malan (20) offered some brief resistance after Haseeb Hameed had been removed for a duck by Jhye Richardson, but the pair were soon sent packing to leave Root and Ben Stokes (3 not out) to try and save the day.

Root, though, fell to Starc's final delivery after he had earlier been hit in the groin by the left-arm quick, and Head appreciated what a big wicket the England captain was.

"Root is a huge wicket, he is in fantastic form," Head told reporters after play ended on the penultimate day at the Adelaide Oval with England 82-4.

"I have a lot of sympathy for him – it wasn't a great time to get hit.

"We got told to give him some space [on the pitch]. Starc on that line is never pretty and unfortunately with the day he [Root] has had it wasn't a great time to get hit.

"They've still got some quality players. Nathan Lyon will play a massive part, the ball is turning. It's a big day tomorrow."

England will need what would seemingly be a miracle on Monday, with Stokes – who delivered unlikely heroics at Headingley in 2019 against the same opposition – leading the charge.

England's fast-bowling coach Jon Lewis expressed his support for Stokes, who he believes is the best man for the task ahead, while hailing the valiant efforts of Root.

"Anytime one of your best players [Root] gets out, it's a knock," Lewis told reporters.

"Joe showed a hell of a lot of character to go out. There was no doubt in Joe's mind he was going out to bat and it shows what a great player and brilliant leader he is. 

"Since he got hit he stood up, he could have had a nightwatchman. He wants to show his team how hard he wants to try for the team.

"They will try to survive the day tomorrow to get ourselves out of this game with a draw. It's a big ask I know."

"Ben [Stokes] has done it before, he has done special things in an England shirt."

Australia still hold a "great advantage" in the first Ashes Test despite England's batting rearguard on day three at the Gabba, says Travis Head.

Head (152) passed 150 for the second time in his Test career on Friday, as Australia took a lead of 278 runs after scoring 425 from their first innings.

He had a batting strike rate of 102.7 in his innings – the second-best by any player to score 100+ runs in a men's Test innings at the Gabba, after Joe Burns (129 runs, 104.9 SR v New Zealand) in November 2015.

Pat Cummins and Mitchell Starc dismissed Rory Burns and Haseeb Hameed respectively to leave England on 61-2, but Joe Root and Dawid Malan led the fightback for the tourists.

Root, who has now scored 1,541 runs in 2021 (the most an England captain has managed in a calendar year), reached stumps on 86 not out, while Malan will resume on 80.

While having had joy with the new ball, Australia struggled to unsettle Root and Malan as the day wore on and batting conditions improved.

Head, however, is still confident the game is in Australia's hands, though he emphasised the importance of a strong start on day four, with England trailing by 58 runs.

"Having seen with the new ball, both last night and in our innings, we've seen it challenging the bat," he told BT Sport. 

"That's going to be the key tomorrow morning is hopefully getting a wicket in those first 10 overs then we get the new ball again, it's going to be key for us.

"If we can hopefully get one or two [wickets] in those 10 overs, hold onto those runs, each one's going to be gold. If we can have five or six wickets at evens we're right in it and still driving that game.

"I think we created opportunities throughout the day. No surprise in the way [Root and Malan] came back out and applied themselves, two quality batsman that have put themselves in a position of fighting back.

"We still hold a great advantage, 60 runs with the new ball round the corner. Still positive and it's going to be a positive morning."

England captain Joe Root and Dawid Malan mounted a fine rearguard to help England get back into the first Ashes Test against Australia with an unbroken 159-run third-wicket partnership.

The tourists reached 220-2 at stumps on day three at the Gabba, trailing by only 58 runs, with Root 86 not out and Malan 80 no.

Australia had added 82 to their overnight score – led by Travis Head, who passed 150 for the second time in his Test career – before being bowled out for 425, with a 278-run lead.

England appeared well behind in the game at 61-2 when Mitchell Starc had Haseeb Hameed (27) caught behind by Alex Carey.

But Root and Malan combined for an excellent partnership, as batting conditions improved on a bright day in Brisbane where only five wickets fell.

Australia had resumed on 343-7, with Head and Starc continuing their 85-run eighth-wicket stand well into the first session before the latter fell for 35. Mark Wood then claimed the final two wickets – including Head with a yorker for 152 – to finish with 85-3.

In response, England opener Burns, who was clean bowled with the first ball of the series, almost fell for a pair when umpire Paul Reiffel gave him out lbw from Starc.

Burns successfully had the decision overturned, with the early bounce taking it over, but did not capitalise on the reprieve for long, caught behind by Carey as Australia skipper Pat Cummins deceived him for 13.

Hameed had played well before he tickled a Starc delivery down leg through to Carey to fall for 27.

However, Root and Malan responded with a gritty stand. The England skipper was clinical off his pads, hitting 10 boundaries, while Malan was excellent square of the wicket, also finding the rope on 10 occasions.

Record for Root

Root's attempt to play at the final ball of the day from Cameron Green almost undid his hard work, but the England captain remains well poised for a 24th Test century and fourth Ashes hundred after being dismissed for a duck in the first innings.

Six of Root's tons have come in 2021 alone, and this knock has now taken him clear of Michael Vaughan (1,481 in 2002) with the most England Test runs in a calendar year (1,541).

Aussie bowling concerns

The first session on day four will be critical for both sides, with only 10 overs left until Australia take the new ball, desperate to get more wickets before England take the lead.

Josh Hazlewood did not bowl in the final session on day three, only getting through eight overs in the second innings in a slight concern for the hosts, while spinner Nathan Lyon has struggled, failing to take a wicket so far in the match.

Travis Head said he is "still pinching" himself after his maiden Ashes century furthered Australia's control in their opening Test against England.

Head, whose position was seemingly in doubt heading into the series, raced to the third-fastest century in an Ashes innings, reaching the landmark in just 85 balls as he took a particular liking to Jack Leach.

The 27-year-old added to his total for an unbeaten 112 at the close of play in Brisbane, with Australia boasting a 196-run lead after England were skittled for 147 in their first innings.

After the end of day two at the Gabba, Head expressed his disbelief at his performance as also credited the work of new Test captain Pat Cummins and Australia's coaching team.

"I'm still pinching myself," Head said post-match. "It's the sort of thing where I can't quite work out what transpired in the last couple hours, but I want to contribute to Australia and Australia wins. 

"Hopefully, we've put ourselves in a nice position. [Thursday] morning is important to continue another great day for Australia and that's what I'm here to do. 

"I was really relaxed throughout the game. Patty and the coaching staff have been fantastic in the way they've handled the last six or seven days and how they've wanted to see me play. 

"They'll go about it and just want to see me be myself and play the game and play how I see it. They've got great confidence in that. 

"I was relaxed over the last two days and I said that going into the camp, it's so enjoyable to be around this group again and contribute in some little way."

Head's bludgeoning that compounded England's misery was earlier set up by David Warner, who managed 94 after multiple missed chances by the tourists, and Marnus Labuschagne crafting 72 to stunt the charge of Joe Root's bowlers.

Indeed, only four men have recorded faster centuries for Australia in men's Test cricket than Head, but the Adelaide-born batter praised the work that went before him in grinding down the likes of Mark Wood, Chris Woakes and Ollie Robinson.

"Today it went my way, but a lot of work was done by the top order and I thought they batted exceptionally well," he added.

"I think both camps would have been talking about that [grinding the opposition down] for the last 10 days and what they want to try to achieve. 

"We spoke about that as a batting group going into this Test in Australia. We said our biggest goal is trying to keep them out in the field. 

"It was extremely hot over the last two days, there are some difficult conditions. There's no doubt that both camps would like to do that as they bat. 

"[England] are going to try and do that in the second innings when they play as well. We've not really talked about it, we'll talk about it in the morning, but I think it's pretty obvious that what we would like to do is continue to bat well for as long as possible and get ourselves in a great position."

David Warner lauded Travis Head and Australia's other batters after they dominated England on day two of the opening Ashes Test.

England were dismissed for only 147 on day one, and Australia put themselves into a commanding 196-run lead on Thursday.

Head (112 not out) scored the third-fastest Ashes century - reaching three figures off only 85 balls - to take Pat Cummins' team onto 343-7 at stumps in Brisbane.

Warner made an impressive 94 after being given a few lives, putting on 156 for the second wicket with Marnus Labuschagne (74) to put Australia in a strong position.

Labuschagne has now scored four half-centuries from five Test innings at the Gabba, with Warner having struck over 50 as an opener for a sixth time at the venue, with only Mark Taylor (eight) doing so on more occasions.

Speaking to Fox Sports, Warner said: "They did bowl well, didn't they? They were relentless.

"What an entertaining innings by Travis Head. We've got smiles on our faces. It's got to be up there for him personally. It was a tight battle with him and Uzzie [Usman Khawaja] but to come out the way he did... that's the Travis Head we know."

Warner's first near-miss came early on, when Ben Stokes bowled him but the all-rounder over-stepped.

"Obviously getting bowled off a no-ball - you've got to try and keep your feet behind the line as a bowler," Warner added.

"I thought I left very well. Everyone was talking about my form in the T20 stuff but when you're out of runs you deserve some luck."

Ollie Robinson was the pick of England's bowlers with 3-48, and the paceman felt his eventual dismissal of Warner had been a long time coming.

"I sort of felt like I was going to get him out every over to be honest," Robinson told Fox Sports.

"He left well in periods but I think he played at a lot of balls he could have left. So hopefully throughout the series I can get his number a bit earlier."

Reflecting on chances going down in the field, with Rory Burns' routine drop from a Warner edge a particular low point, Robinson added: "We did miss opportunities early on but on another day we could have had three or four early.

"It came out well. It felt like I was consistent and had a lot of play and misses. The closest thing we have [to the Gabba] is Headingley. It's nice to get that bit of extra bounce as a tall guy."

Robinson did pull up with an apparent hamstring issue, but revealed it was only a minor problem.

"It's okay," he said. "I came off for a bit of strapping, bit of maintenance but it's alright, rest up tonight and go again tomorrow."

Travis Head hit his first Ashes century as Australia reached 343-7 to take control of the first Test in Brisbane.

Head's place in Australia's line-up was under some scrutiny heading into the series, but the decision to give him the nod over Usman Khawaja paid off emphatically and he is still in place on 112 not out heading into day three.

His century came after David Warner fell just short of a ton, striking 94 before falling to Ollie Robinson, the pick of England's bowlers with 3-48.

A blow to the underside of Head's chin from an errant Mark Wood delivery could not even dampen Australia's mood.

England were desperate for a fast start after a nightmare opening day at the Gabba, where the tourists were skittled for 147.

Joe Root's men got what they wanted – Ashes debutant Robinson making the early breakthrough when he had Marcus Harris (3) caught at slip.

Ben Stokes knocked over Warner for 17 but he was afforded a reprieve with a no-ball call, while Marnus Labuschagne's edge fell agonisingly short of Root.

Warner was granted two more lives following lunch – Rory Burns dropping a routine catch on 49, while the opener was stranded outside his crease on 60 – but Jack Leach's dismissal of Labuschagne sparked England.

Four wickets in the space of eight overs followed. Warner, Cameron Green (0) and Steve Smith (12) all sent to the pavilion as Robinson just missed out on a hat-trick.

Despite the wickets of Alex Carey (12) and captain Pat Cummins (12), England – walking wounded with Stokes struggling and most of their attacking fading in the sun – were unable to maintain their charge.

Head surpassed his century with a sublime on-drive from Chris Woakes and though Wood's beamer did deliver a blow to the batsman's jaw, his efforts moving Australia into a 196-run lead.

Head stars as team-mates set the stage

Head could well have put this game out of England's reach. His innings so far has included 12 boundaries and two sixes. Only four players have scored a faster hundred for Australia in a men's Test innings (Adam Gilchrist, Jack Gregory, Warner, Matthew Hayden).

While they did not have centuries to show for their efforts, Warner and Labuschagne enjoyed stellar days. Warner posted his sixth 50-plus score as an opening batsman at the Gabba, equalling Bill Lawry for the second most at the ground in the format as an opener – only Mark Taylor (eight) has more. Labuschagne, meanwhile, recorded his fourth 50-plus score in five career innings at the Gabba.

No-ball embarrassment

Umpiring and technology were in the spotlight for all the wrong reasons after Stokes' early spell. Having been denied the wicket of Warner due to a no-ball, analysis of his spell showed the England star had overstepped 14 times with only two no-balls called. The reason? The technology had failed, leaving the umpires to make the calls.

As for Stokes, he finished with disappointing figures of 0-50 from nine overs, suffering a knee injury in the field to further compound a so-far frustrating return.

Australia have opted for Travis Head over Usman Khawaja as captain Pat Cummins confirmed the starting XI to face England in the opening Ashes Test at the Gabba.

It was between Head and Khawaja in the race to bat at number five in Wednesday's opener in Brisbane and Australia stuck with the former.

Head, who played in four of the 2019 Ashes Tests and top-scored with 51 at an average of 27.28 before sitting out the final match, has made 394 runs – including two centuries – at 49.25 this Sheffield Shield season.

His overall Test record also stands at an average of 39.75 from 19 matches, including two tons.

Khawaja – without an international appearance in the longest format of cricket since the third Ashes Test in 2019 – also had a pair of hundreds as part of a 460-run haul at 65.71 in the Sheffield Shield.

But new Australia skipper Cummins and selectors preferred Head as they bid to retain the urn, though England are yet to confirm their XI.

"It was a tight one. Both really good options, really strong form," said Cummins on Sunday.

"Experience is great from Uzzie and we feel really lucky to have that in the squad, but Trav's been playing a lot for us the last couple of years.

"He's gone away and he's churned out runs in England, here in Australia, and we feel like he's really ready to go."

Australia quick Mitchell Starc avoided the axe, selectors keeping faith with the paceman alongside fellow pace bowlers Cummins and Josh Hazlewood.

Starc's position was under threat due to his form and the rise of Jhye Richardson, who had taken 15 wickets in his past two Sheffield Shield matches.

England captain Joe Root declined to announce his team during Sunday's series launch, telling reporters: "We've got all the options on the table [but] we're not going to name a team just yet.

"We'll have to see the closer forecase and how that pitch changes over the next couple of days.

"But it's a great place to play spin. It's something we'll weigh up and consider, but we're not in a position to make that call right now."

Australian XI: David Warner, Marcus Harris, Marnus Labuschagne, Steve Smith, Travis Head, Cameron Green, Alex Carey, Pat Cummins (c), Nathan Lyon, Josh Hazlewood, Mitchell Starc.

England: Joe Root (c), James Anderson, Jonathan Bairstow, Dom Bess, Stuart Broad, Rory Burns, Jos Buttler, Zak Crawley, Haseeb Hameed, Dan Lawrence, Jack Leach, Dawid Malan, Craig Overton, Ollie Pope, Ollie Robinson, Ben Stokes, Chris Woakes, Mark Wood.