Elena Rybakina and Jessica Pegula will face off for a place in the Indian Wells Open semi-finals.

Reigning Australian Open champion Rybakina, who beat Pegula en route to her triumph in Melbourne, progressed as Sonay Kartal was forced to retire hurt from their last-16 tie.

Rybakina was leading 6-4 4-3 at the time of Kartal's withdrawal.

Pegula, meanwhile, ousted Belinda Bencic, claiming her first win over the Swiss.

"Had to turn the tables," Pegula said after snapping her four-match losing run against Bencic.

"[Now], nobody beats me five times in a row. She's been a really tough opponent for me, but I feel like since the last I played her, I'm a different player.

"I think I'm a much better player now, but I also think that tactically I definitely changed some stuff. I serve much better now, which helps me out not feeling so much pressure with her returning, because she's a really good returner.

"I think tactically I don't want to totally give away what I have been doing, but there was definitely some stuff that I have seen that I've gotten better at that I'm able to adapt to in a point that I'm able to just think a little bit more clearly and quicker out there."

Elina Svitolina also progressed to the quarters via a walkover, with Katerina Siniakova retiring during the second set of their contest.

Data Debrief: Pegula in her prime

Since the format's introduction in 1990, Pegula – at the age of 32 years and eight days – is now the oldest player to reach 20+ Tier I/WTA 1000-level quarter-finals on hard courts, surpassing Venus Williams (31y, 275d).

In fact, only three women can boast a higher win rate at Tier I/WTA 1000 events than Pegula (75%, 45-15) after turning 30 – Serena Williams, Martina Navratilova and Mary Pierce.