Three-time grand slam winner Angelique Kerber suffered a back injury that forced her to withdraw from the Adelaide International on Wednesday with the Australian Open just around the corner.

Kerber, who won the Australian Open in 2016, had lost the first set to Dayana Yastremska 6-3 and was a break down in the second when she required on-court medical assistance.

After being put through a series of stretches, the former world number one decided she was unable to carry on and retired, allowing Yastremska to reach the last eight of the competition, where she will meet Donna Vekic after her 2-6 7-5 6-1 win over Maria Sakkari.

The most impressive win of the day belonged to Marketa Vondrousova, however, as last year's French Open runner-up claimed a stunning 6-0 6-0 victory over home hope Arina Rodionova, setting up a meeting with another Aussie in the quarters – world number one Ash Barty.

Vondrousova, 20, is taking part in her first tournament since Wimbledon after undergoing wrist surgery in September and will be out for revenge against Barty, who beat her at Roland Garros in June.

Fourth seed Belinda Bencic came through a tight tussle with Julia Goerges to emerge a 7-6 (8-6) 7-6 (7-4) victor, with her last-eight opponent Danielle Collins having significantly less difficulty against fellow American Sofia Kenin – the unseeded 26-year-old winning 6-3 6-1.

The fourth quarter-final will see Aryna Sabalenka go head-to-head with Simona Halep, after the Belarussian sixth seed eliminated Bernarda Pera 7-6 (7-4) 6-2.

Elise Mertens remains on course for a third Hobart International title after the top seed dropped single game in her 6-1 6-0 defeat of Viktoria Kuzmova, setting up a quarter-final with Great Britain's Heather Watson, a 7-6 (7-5) 6-3 winner against Fiona Ferro.

Aussie wildcard Lizette Cabrera claimed a 4-6 6-4 6-4 upset over Kristyna Pliskova, while second seed Garbine Muguruza edged past Ons Jabeur 3-6 6-3 7-6 (7-4) and will face Veronika Kudermetova.

Shuai Zhang, Lauren Davis and Elena Rybakina are also into the quarter-finals following respective triumphs over Kateryna Kozlova, Magda Linette and Alize Cornet on Wednesday.