American Madison Keys upset sixth seed Elena Rybakina 6-3 1-6 6-3 in a roller-coaster match at Margaret Court Arena to march into the quarter-finals of the Australian Open on Monday and extend her win streak to nine matches this year.
Adelaide Open champion Keys had lost to the Kazakh in their last two encounters but was well in control for most of the last 16 tie, barring a rough patch in the second set when she lost four straight games.
Rybakina seemed to be struggling with a lower back injury that had affected her in the third round and Keys was able to play aggressively to neutralise her big serve and take control of the rallies.
“Her serve is such a weapon, so I knew that if I could just try to make at least some of her service games a little bit competitive, then I had a chance,” said the 19th seed, who chalked up her third win over a top-10 player this month.
“So I was basically just trying to make anything that I could get my racket on back over the net, which worked sometimes.”
The decider was neck-and-neck early on at 3-3 before Keys moved up a gear and sealed her spot in the next round with a searing cross-court winner on her second match point.
She will next play Ukraine’s Elina Svitolina, who beat Veronika Kudermetova 6-4 6-1 earlier on Monday.