Coco Gauff fought from a set down to beat Belinda Bencic and join defending champion Aryna Sabalenka in the Australian Open quarter-finals.
The American third seed was not at her best but outlasted Switzerland’s Bencic 5-7 6-2 6-1.
Earlier, Sabalenka breezed past Russian 17-year-old Mirra Andreeva in a 6-1 6-2 victory.
Gauff’s victory in 34 degree heat – the hottest day of the tournament so far – extended the 20-year-old’s winning run to 11 matches.
“Maybe a couple of years ago, if I lost the first set I might lose the match, and I remember my dad said ‘we’ve got to toughen you up’,” said Gauff.
“I was just trying to put myself in the position where I could leave the court and feel proud of myself.”
Belarusian top seed Sabalenka, 26, meanwhile, remains on course for a third straight Australian Open title after wrapping up her win over Andreeva in just 62 minutes on Rod Laver Arena.
It was the two-time champion’s 18th win in a row at Melbourne Park, and sets up a quarter-final against another Russian, Anastasia Pavlyuchenkova.
Pavlyuchenkova beat Croatia’s Donna Vekic 7-6 (7-0) 6-0 in the fourth round earlier on Sunday.
Gauff will play 11th seed Paula Badosa in the last eight after the Spaniard defeated Serbia’s Olga Danilovic 6-1 7-6 (7-2).
Should they both win their quarter-finals, Sabalenka and Gauff will meet in the semi-finals.
