Serena Williams has crashed out of the Australian Open at the quarterfinal stage after a 4-6, 6-4, 5-7 defeat to seventh seed Karoline Pliskova of the Czech Republic.

Williams, 37, squandered four match points after leading 5-1 in the final set but her bid for a record-equaling 24th Grand Slam title ended as the Czech came back to set up a semifinal meeting with Naomi Osaka, who defeated Williams in last year's final.

At 5-1 down in the deciding set, Pliskova admitted her "mind was already in the locker room."

"It was tough because she [Williams] was really playing well I didn't have many chances in the third set," she continued. "I was a little bit too passive and obviously mentally down but I just thought: 'let's try this game.'

And so with Williams seemingly having injured her ankle, the 26-year-old former world No. 1, who was beaten in the 2016 Australian Open final by Germany's Angelique Kerber, came racing back.

Earlier in the day fourth seed Osaka of Japan had made short work of Ukraine's Elina Svitolina 6-4, 6-1.

Pouille praises Mauresmo as he reaches first semi

In the men's draw, France's Lucas Pouille reached his first ever Grand Slam semifinal after seeing off Canada's Milos Raonic 6-6 (7-4), 6-3, 6-7 (2-7), 6-4.

Pouille, 24, became only the second man at the top of men's tennis to employ a non-related female coach when Andy Murray's former coach Amelie Mauresmo joined his team last year – and the 39-year-old former Grand Slam winner's influence is clearly having an effect.

"She has the right set of mind and she knows everything about tennis," he said in the on-court interview. "It's not about being a woman or a man. It doesn't matter. You just have to know what you're doing and she does."

Djokovic through after Nishikori retires

Pouille will play world No. 1 Novak Djokovic after eighth seed Kei Nishikori retired in the second set of their quarterfinal. 

After coming through three five-set marathons just to reach the last-16, Nishikori suffered a thigh injury in the opening set which he went on to lose 1-6. He retired at 1-4 down in the second to send Djokovic through. 

mf/pfd (AP, dpa)