A tireless Kei Nishikori shocked 17-time grand slam winner Roger Federer 3-6, 7-5, 6-4 to claim his second top-five scalp in two days and reach the semi-finals of the Sony Open.

After knocking off fourth-seed Spaniard David Ferrer in a three-hour marathon on Tuesday, the 21st ranked Japanese was forced to go the distance again, surviving a two-hour centre court battle with Federer.

Nishikori has been one of Federer's few bogeymen, having now gotten the better of the Swiss maestro in two of their three career meetings.

"To beat Roger, and it's second time to beat him... I thought I really played well, especially in the third," Nishikori told reporters. "I was hitting both deep and striking well. Everything was going well. There was couple of tough moments, but I was fighting through and happy to win today."

Djokovic beats Murray

In the other quarter-final, world number two Novak Djokovic ended Andy Murray's reign as Miami champion by easing past the sixth-seeded Briton 7-5, 6-3.

For Djokovic, the victory over Murray was a small measure of revenge as the met for the first time since the Scotsman beat him in last year's Wimbledon final. Murray, playing his first event since splitting with coach Ivan Lendl last week, had looked increasingly comfortable and confident on his own but Djokovic kept the Scotsman under almost constant pressure in blustery conditions.

In the women's draw, world number two Li Na powered her way past 11th-seed Caroline Wozniacki 7-5, 7-5 and into the semi-finals, setting up another rematch of the Australian Open final against Slovakia's Dominika Cibulkova.

Cibulkova had earlier fought off three match points to claim a 3-6, 7-6, 6-3 upset win over third-seed Agnieszka Radwanska of Poland, propelling her into the top 10 for the first time in her career.

Source: Reuters