World number two Aryna Sabalenka's hopes of reaching a fourth consecutive Stuttgart Open final ended after a 3-6 6-3 7-5 quarter-final defeat by Marketa Vondrousova on Friday, while champion Iga Swiatek maintained her perfect record at the event.

World number one Swiatek extended her run at the tournament to 10-0 and is now two wins away from claiming a third successive Stuttgart title following her 7-6(2) 6-3 win over Briton's Emma Raducanu.

She will face fourth seed Elena Rybakina for a place in Sunday's final.

Sabalenka had won her last four matches with Vondrousova, and after winning the opening set, the Australian Open champion looked on course to progress.

Wimbledon champion Vondrousova led 4-1 in the second set before Sabalenka pulled it back to 4-3 but the Czech sixth seed broke for a third time and held serve to force the decider.

ALSO READ: WTA roundup: Iga Swiatek remains perfect in Stuttgart

Sabalenka went 5-4 ahead in the final set before Vondrousova reeled off three games in a row to reach the semi-finals where she will meet either American third seed Coco Gauff or Marta Kostyuk of Ukraine.

Fourth seed Elena Rybakina also reached the semi-finals after overcoming the challenge of in-form Jasmine Paolini 6-3 5-7 6-3

"It was a very tough match, and I think a great one, too," Vondrousova said.

"She's a great player so I just tried to stay in the rallies. She hits very fast so it's tough to do something. But I stayed calm in the crucial moments."

Sabalenka reached the quarter-finals after her good friend Paula Badosa was forced to retire through injury on Wednesday, with the match tied at one set each and 3-3 in the decider.

Fourth seed Elena Rybakina also reached the semi-finals after overcoming the challenge of in-form Jasmine Paolini 6-3 5-7 6-3.

Paolini won the Dubai Tennis Championships in February and rose to a career-high 14th in the world rankings and reached the last 16 at Indian Wells in March.

READ MORE: WTA1000 Wuhan Open to return in October

After winning the opening set, Rybakina had let slip a 4-2 lead in the second and came back from an early break by the Italian in the final set.

"I'm happy with my energy," Rybakina said.

"Of course, I had chances in the second set where I could have closed it out but overall, I think it's just a matter of matches and feeling better and better on the court."