Top seed Johanna Konta started her grass-court season with a straight-sets victory over Lesley Pattinama Kerkhove in the second round of the Nottingham Open.

Konta parted with her coach Dimitri Zavialoff for a second time after crashing out of the French Open at the hands of Sorana Cirstea in the first round.

The British number one was back in business on home soil on Tuesday, dispatching Pattinama Kerkhove 6-1 6-3.

Kateryna Kozlova will be Konta's next opponent after she upset 13th seed Madison Brengle 6-3 5-7 6-3.

Donna Vekic, the third seed from Croatia, breezed into the third round with a 7-5 6-1 success over Leonie Kung.

Viktorija Golubic also progressed, having won the first set 6-1 before Kristie Ahn retired, while Nina Stojanovic got the better of Oceane Dodin 7-6 (7-4) 7-5.

Georgina Garcia Perez fought back to knock out 18th seed Christina McHale, and there were also wins for Tereza Martincova and Zarina Diyas.

Jil Teichmann saved six match points in a stunning defeat of Elina Svitolina before Ash Barty breezed into the second round of the Madrid Open on Thursday.

Teichmann produced an astonishing fightback to beat fourth seed Svitolina 2-6 6-4 7-6 (7-5) at the Caja Magica.

Unseeded Swiss Teichmann came from a set and a break down to claim the scalp of the world number five, who squandered a commanding 5-1 lead in the final set.

Svitolina saw six match points come and go in an incredible deciding set, opportunities she was left to rue when the 40-ranked Teichmann won a tie-break to end a contest that took two hours and 33 minutes to settle.

World number one Barty extended her winning run on clay to 12 matches with a 6-2 6-1 success over Shelby Rogers.

Barty claimed her third title of the year in Stuttgart last weekend and the Australian needed just an hour to send Rogers packing, losing just two points on her first serve and not facing a single break point.

French Open champion Iga Swiatek was also an emphatic winner, easing past another American in the form of Alison Riske 6-1 6-1.

Swiatek, making her debut in this tournament, has won 16 consecutive matches on clay after blowing Riske away.

Defending champion Kiki Bertens beat 15-year-old Victoria Jimenez Kasintseva 6-4 6-0, while Petra Kvitova progressed when opponent Marie Bouzkova retired due to hand injury after the Czech won the first set.

Garbine Muguruza was forced to withdraw ahead of her meeting with Sloane Stephens due to a leg injury. Belinda Bencic, Angelique Kerber and Johanna Konta were among the other winners in the Spanish capital.

Teen stars Iga Swiatek and Coco Gauff earned Adelaide International victories on Tuesday, but third seed Johanna Konta is out.

French Open champion Swiatek secured a 6-3 6-4 triumph over Madison Brengle to set up a last-16 tie against home favourite Maddison Inglis, who beat veteran Sam Stosur in a three-set epic.

"Inside I'm the same person, but I realise that everybody's kind of treating me differently," Swiatek said after the win, as she reflected on the attention she now receives as a grand slam champion.

"So it's something you have to adjust to, and also keep yourself down to earth and the same as you were.

"We did a great job last year and hopefully this season will also be successful. 

"Tennis-wise it also changes - I’m not an underdog anymore, so I start my matches with a different attitude, and that’s the kind of thing you have to learn to do.

"Madison is the kind of player who uses her opponent's power, so I had to stay cool. 

"I tried to calm myself down, stay low in the legs, and sometimes play longer rallies to get in the rhythm, because the first round is always tough at any tournament."

Gauff also progressed, saving eight of the 11 break points she faced to defeat Jasmine Paolini 6-4 6-7 (4-7) 6-2 in a match lasting over two-and-a-half hours.

A tough test against Petra Matric is up next for Gauff in the last 16 after the Croatian sixth seed recovered from a set down to win against qualifier Ludmilla Samsonova.

Gauff's fellow American Shelby Rogers is the first player to reach the quarter-finals.

Konta had a bye in the opening round and had no answers for Rogers as she played her first match of the WTA 500 tournament.

Rogers won 6-2 6-2 in just 76 minutes, never dropping serve in the contest.