Canada's Bianca Andreescu upset Greek seventh seed Maria Sakkari 5-7, 6-3, 6-4 to reach the Miami Open third round on Friday, while Russia's Andrey Rublev survived a tough battle against American JJ Wolf to reach the last 32. 

The 22-year-old Andreescu, ranked 31st in the world, has struggled with injuries and form in recent years and is eyeing her first title since the 2019 U.S. Open. She fought back strongly after dropping the first set and subsequently denied Sakkari a chance to find her rhythm as she clinched victory in three hours. 

"Last time I played her, I cramped, so I'm just super happy that I got through physically," Andreescu, recalling her late-night, three-and-a-half hour fourth-round encounter with Sakkari at the 2021 U.S. Open, said in her on-court interview.

Andreescu has now claimed three wins over top ten opponents since returning to the tour last April from a six-month mental health-related hiatus.

In another surprise, fourth seed Ons Jabeur also crashed out, losing her opening match to Russian qualifier Varvara Gracheva 6-2, 6-2.

Karolina Pliskova of the Czech Republic advanced with a 6-2, 6-4 win over China's Wang Xinyu and her compatriot Barbora Krejcikova also enjoyed a straight sets win, 6-3, 6-2, against Belarusian Aliaksandra Sasnovic.

In the men's draw, sixth seed Rublev was broken in the opening game against Wolf and trailed for much of the first set, but fired 16 aces in the match and was a threat from the baseline as he secured a 7-6(3) 6-4 win in 41 minutes.

Defending men's champion Carlos Alcaraz, who arrived in Miami looking to add to his Indian Wells title and complete the "Sunshine Double," swept Argentina's Facundo Bagnis 6-0, 6-2.

Spanish top seed Alcaraz, who did not drop a set at Indian Wells, must retain his Miami crown to stay ahead of Serbian Novak Djokovic and hold on to the top spot in the rankings.

Norway's Casper Ruud and America's top-ranked Taylor Fritz also advanced into the last 32.

(With input from agencies)