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British number one Johanna Konta has been knocked out of the Miami Open in the fourth round by three-time champion Venus Williams.

Defending champion Konta, ranked 14th in the world, won the first set but eventually lost 5-7 6-1 6-2.

The 26-year-old had beaten world number eight Williams in straight sets in the semi-finals 12 months ago.

Williams, 37, will play fellow American Danielle Collins, who beat Monica Puig 3-6 6-4 6-2, in the quarter-finals.

The first set lasted just over an hour and Konta saved set point to turn it in her favour and take the early advantage.

But Williams, a seven-time Grand Slam singles champion, cruised through the second set to even the score, with Konta requiring a medical timeout before the deciding set.

The Briton hit three aces in a row to save a break point in the third set, but Williams continued her dominant comeback to serve for the match.

Slam winners dominate quarter-final draw

Williams is one of five Grand Slam winners to reach the last eight in Key Biscayne.

US Open champion Sloane Stephens eased past Spanish third seed Garbine Muguruza, the reigning Wimbledon champion, with a 6-3 6-4 victory in one hour and 28 minutes.

Germany's two-time Grand Slam winner Angelique Kerber will face Stephens after defeating Yafan Wang of China 6-7 (1-7) 7-6 (7-5) 6-3, while Belarusian Victoria Azarenka, a two-time winner of the Australian Open, beat Agnieszka Radwanska of Poland 6-2 6-2.

She meets Czech Republic's fifth seed Karolina Pliskova, who won when Zarina Diyas of Kazakhstan retired hurt while trailing 6-2 2-1.

Fourth seed Elina Svitolina of Ukraine advanced with a 7-5 6-4 win over Australian Ashleigh Barty and will play Latvia's Jelena Ostapenko.

Ostapenko - who won last year's French Open - completed the quarter-final line-up with a 7-6 (7-4) 6-3 win over Czech Petra Kvitova.