Halep had been on a collision course with French Open champion Barty in the last four having been placed in the same half of the draw.

However, Halep's tournament came to an end on Wednesday as a back injury forced her retirement when trailing 5-4 in the first set to Rybakina, who will next face defending champion Aryna Sabalenka.

Barty came through in relatively comfortable fashion against Sofia Kenin, but there was a shock in the other half of the draw as Dayana Yastremska knocked out Karolina Pliskova, who can now not claim top spot in the rankings at the end of the week.

BARTY BREEZES THROUGH

A tougher test may have been expected against one of the rising stars of the WTA Tour in Kenin, but Barty needed only an hour and 26 minutes to dispatch the No.15 seed 6-3 7-5.

The Australian had been a break down in the second set and saved a pair of set points, avoiding a decider to complete a third win in four meetings with Kenin this season.

Assessing her performance, Barty said: "I can sit here and pick my game apart and be super critical, but I also have to be able to take away the really good stuff, the good times that we've been able to get out of these matches - particularly the last 20-odd points today. I felt like I got on a real run there."

Petra Martic awaits Barty in the quarter-finals after seeing off Veronika Kudermetova in straight sets.

SABALENKA ROARS TO FIRST WIN OVER BERTENS

Sabalenka had never previously beaten Kiki Bertens in four attempts before their meeting in Wuhan, and she appeared in danger of throwing away a commanding position as she let slip a 5-1 second-set lead.

The Belarusian spurned four match points but recovered her composure to save a Bertens set point and win the decisive tie-break. 

Her 6-1 7-6 (11-9) success means Sabalenka has won 15 straight sets in Wuhan, rediscovering her enjoyment of competition after travelling to the recent Zhengzhou Open without coach Dmitry Tursunov.

"The tiger is back," she said. "I'm just playing freely, not afraid of anything and just going for shots. Every time before the match I can't wait to go out and to play, and I'm so happy to feel this again."

YASTREMSKA CLAIMS FIRST TOP 10 SCALP

Teenager Yastremska has enjoyed an excellent 2019, winning titles in Hua Hin and Strasbourg while reaching the fourth round at Wimbledon and the third round at the Australian Open and US Open.

She added to an increasingly impressive resume by stunning No.2 seed Pliskova to claim the first top-10 win of her fledgling career.

The 19-year-old needed only 64 minutes to surge to a 6-1 6-4 win. Yastremska did not drop serve and hit 26 winners to just 15 unforced errors to put Pliskova's hopes of displacing Barty on hold.

Yastremska will face Petra Kvitova for a place in the semi-finals after the two-time champion overcame Sloane Stephens 6-3 6-3. The other quarter-final will see Elina Svitolina take on Alison Riske after their wins over Svetlana Kuznetsova and Wang Qiang respectively.