MIAMI (REUTERS, AFP) - Venus Williams upended defending champion Johanna Konta 5-7, 6-1, 6-2 on Monday (March 26) to reach the Miami Open quarter-finals, while a dominant Victoria Azarenka also advanced with a straightforward win over Agnieszka Radwanska.
And Sloane Stephens powered past world No. 3 Garbine Muguruza, as the seeds continued to fall.
Three-time champion Williams stormed back from an early deficit to cruise past the British 11th seed, who needed several bouts of treatment on her lower back throughout a match that lasted two hours and 19 minutes.
Perhaps more impressive was that Williams, who turns 38 in June, was able to look so in control despite playing a day after spending nearly three hours on the court for her third-round win over Dutchwoman Kiki Bertens.
"The first set was definitely all her, and she came up with some amazing shots to break me at 5-all," she told reporters. "There was not much I could do there, except hope I could keep up in the second and third sets."
Former world No. 1 Azarenka, in only her second event after an eight-month absence because of a custody dispute involving her son, also looked sharp throughout her 6-2, 6-2 win over 30th-seeded Pole Radwanska.
The Belarusian, competing as a wild card, won 79 per cent of her first service points and needed only 82 minutes to prevail in a clash between former Miami champions.
Up next for the 28-year-old is Czech fifth seed Karolina Pliskova, who advanced to the last eight after Zarina Diyas of Kazakhstan was forced to retire injured while trailing 6-2, 2-1.
"(Pliskova) is an amazing player, a top 10 player," Azarenka said. "For me, it's a challenge to see how I can approach that and how I can progress from that match. It's perfect. I wouldn't ask for anything else."
Former world No. 1 Pliskova was efficient from the start and did not drop a point on her first serves in the entire match against Diyas, who took multiple medical time-outs and was visibly struggling with her movement.
US Open champion Stephens dominated Spain's reigning Wimbledon champion Muguruza to record a 6-3, 6-4 win and advance to the quarter-finals.
Stephens, the world No. 12, will face Germany's Angelique Kerber for a place in the semi-finals. Kerber, yet another ex-world No. 1 in the tournament, was made to sweat in her gruelling clash with China's Wang Yafan before prevailing 6-7 (1-7), 7-6 (7-5), 6-3.
Muguruza had been the highest-ranked player left in the women's draw following the early exits of world No. 1 Simona Halep and Caroline Wozniacki in the earlier rounds.
Kerber's victory continues a remarkable run of results since the turn of the year. The world No. 10 has played six tournaments in 2018 and reached the quarter-finals or better in each event.