Top seed Daniil Medvedev came through a dramatic clash against Alexei Popyrin to seal his place in the fourth round of the Miami Open.
Also progressing to the last 16 was Medvedev’s fellow world No.2 Naomi Osaka, who advanced without hitting a ball when opponent Nina Stojanovic withdrew because of a right thigh injury.
Later on Sunday, Ons Jabeur upset No.4 seed Sofia Kenin before Bianca Andreescu got past Amanda Anisimova in a compelling battle lasting almost three hours under lights.
DRAW: Miami Open women's singles
The 2019 US Open champion’s victory sets up a fourth-round meeting with Garbine Muguruza, who improved to 20-4 in 2021 thanks to a three-set win over Anna Kalinskaya.
Young guns Jannik Sinner and Emil Ruusuvuori will play for a quarterfinal place after both came through their third-round matches in three sets.
Medvedev led Popyrin by a set and 5-2, then held three match points at 0-40 in the 10th game, only for the Australian to rebound and send the match into a third set.
As the match wore on Medvedev began cramping badly, but despite hampered movement the Russian broke Popyrin in the seventh game and eventually served out a 7-6(3) 6-7(7) 6-4 win.
“At the end it was just that I almost couldn't walk. My legs were, again, not following me,” said Medvedev, who has won 16 of 18 matches in 2021, including his past six straight.
Ultimate Warrior Spirit ?@DaniilMedwed battled through the pain barrier in the closing stages to defeat Popyrin at @MiamiOpen... pic.twitter.com/RihFcQQ3HT
— Tennis TV (@TennisTV) March 29, 2021
“Usually in these moments, you're not even thinking about winning. You're just thinking, okay, how can I maybe stay in this match or something like this.
“The funny thing is that I should have won in two sets. We would not be talking about any of these things. But here we are, so yeah, a match to remember, for sure.”
Medvedev, seeking a fourth ATP Masters 1000 crown, will next take on either No.16 seed Dusan Lajovic or American Frances Tiafoe.
Also advancing to the last 16 were 2018 Miami Open champion John Isner – who sneaked past Felix Auger-Aliassime in two tiebreaks – and seventh seed Roberto Bautista Agut, who recovered from a set down to see off Jan-Lennard Struff.
DRAW: Miami Open men's singles
Another three-set winner was Taylor Fritz, who got past Cameron Norrie 6-4 3-6 6-1.
Like Medvedev, Andreescu – playing just her third event after more than 15 months on the sidelines – led by a set and a break before Anisimova elevated her clean baseline game in the second-set tiebreak.
Andreescu required an off-court medical timeout to treat a back issue and it seemed to help loosen her up; the Canadian broke Anisimova in the fifth game and sealed the win with a backhand winner up the line.
"I'm super happy. It's really nice playing back here. Amanda played really, really well. I'm super happy with how I fought through, because it wasn't easy,” Andreescu said.
It will be a tough task next up against Muguruza, who extended her winning streak to eight matches with a 4-6 6-3 6-4 win over Kalinskaya.
"She's been playing well,” Andreescu said of the Spaniard. “I played her in Indian Wells (in 2019) so I know a little bit of what to expect, but it's a different year.
“I'm feeling good. I'm feeling confident.”
She’s a survivor ??
— wta (@WTA) March 29, 2021
The No.8 seed @Bandreescu_ defeats Anisimova, 7-6(4), 6-7(2), 6-4.
Will face Muguruza next.#MiamiOpen pic.twitter.com/53A0kyvdba
Another player continuing their great form was Jessica Pegula, who beat No.6 seed Karolina Pliskova for the third straight time in 2021.
The 29th seed trailed 4-2 in the final set before reeling off the last four games to set up a meeting with Maria Sakkari, a 6-0 6-1 winner over qualifier Ludmilla Samsonova.
Spain’s Sara Sorribes Tormo backed up her win over AO 2021 finalist Jennifer Brady with an upset of No.21 seed Elena Rybakina; she will next play Jabeur, whose win over Kenin was just her second in seven meetings with the AO 2020 champion.
Elise Mertens, the 16th seed, recorded a 6-2 0-6 6-2 win over Anett Kontaveit and will take on Osaka for a place in the quarterfinals.
Mertens, 13-2 in 2021, will attempt to end Osaka’s 22-match winning streak.