Venus Williams ousts defending champ Konta in Miami
The world number eight – a three-time winner in Miami – eliminated the briton while Jelena Ostapenko joins Kerber and Stephens in the quarter-finals.
Venus Williams ended Johanna Konta's title defence at the Miami Open, where reigning Roland Garros champion Jelena Ostapenko also advanced to the quarter-finals.
Williams – a three-time winner in Miami – eliminated the defending champion following a gruelling three-set battle.
The eighth-seeded American lost the opening set against Konta but rallied to move through to the last eight.
French Open titleholder Ostapenko overcame the elements to see of Petra Kvitova after US Open champion Sloane Stephens and two-time grand slam winner Angelique Kerber also progressed to the quarters.
Meanwhile, former world number one Victoria Azarenka accounted for Agnieszka Radwanska to earn a date with fifth seed Karolina Pliskova.
Venus battles past Konta
The 37-year-old recovered from a slow start to triumph 5-7 6-1 6-2 on Monday.
Konta drew first blood after taking the opening set in Miami before Williams came storming back to oust the Brit in two hours, 21 minutes.
"The first set was definitely all her, and she came up with some amazing shots to break me at 5-5," Venus said in her on-court interview. "There was not much I could do there, except just hope I could keep up in the second and third sets."
Next up for Williams is countrywoman and qualifier Danielle Collins, who upstaged Monica Puig 3-6 6-4 6-2.
Ostapenko overcomes Kvitova and the rain
The sixth seed did not let the wet weather ruin her flow as she defeated fellow seed Kvitova 7-6 (7-4) 6-3 in the early hours of Tuesday morning.
Rain halted proceedings with ninth seed Kvitova leading 3-2 in the first-set tie-break.
But when play resumed, Ostapenko blitzed the two-time Wimbledon champion for her maiden Miami Open quarter-final appearance.
Ukrainian fourth seed Elina Svitolina awaits after she saw off Ashleigh Barty 7-5 6-4.
Stephens wins battle of the Slam holders
In a meeting between the US Open champion and Wimbledon winner, it was Stephens who prevailed 6-3 6-4 against Garbiñe Muguruza.
Stephens – the 13th seed – had failed to beat a top-10 player in over half a year, while the American had not won three matches in a row during that period.
But Stephens was a class above as she reigned supreme in the round of 16.
Next up for Stephens is 10th seed Kerber, who survived to beat world number 125 Wang Yafan 6-7 (1-7) 7-6 (7-5) 6-3.
The winner of that showdown will crack the WTA's top 10 and Stephens said: "I will be happy, because I'm tired of people saying, 'And her career high ranking is 11 in the world. Hopefully one of these days, sometime soon, I'll be able to break it... It will be a good step. That one spot will really determine a lot of things."