Kvitova in, Sharapova out at US Open

Twice Wimbledon winner Petra Kvitova of Czech Republic edged past third seed Garbine Muguruza of Spain to make last eight while Russian star Maria Sharapova was ousted by Anastasija Sevastova from Latvia in the fourth round of the US Open on Sunday.

The 13th-seeded Kvitova, battling back after a home-invasion knife attack last December, upset Muguruza with an emphatic 7-6(3), 6-3 triumph.

Muguruza came out firing and built a 4-1 lead over Kvitova. But the Czech battled her way back, saving a break before fighting to take the first set 7-6(3) in 64 minutes.

In the second set, 2017 Wimbledon champion Muguruza seemed as though she could not recover from the tough tiebreak. Kvitova continued to dominate and closed out the win in one hour and 45 minutes.

Kvitova will play seven-time major champion Venus Williams of the United States on Tuesday with a semifinal berth at stake. Williams, seeded No.9, beat Carla Suarez Navarro from Spain 6-3, 3-6, 6-1 earlier on the day.

Kvitova still hasn't quite regained full strength in her left hand, the one operated on after being cut by an intruder at her home in the Czech Republic in December.

"Given all she's been gone through, playing at this level is remarkable," Muguruza said.

Sharapova's Grand Slam return after a 15-month doping ban ended with the fourth round defeat to 16th seed Sevastova.

Despite the heartbreaking loss, the five times Grand Slam winner Sharapova said it's been a really great ride at Flushing Meadows this week and can take a lot positives from the matches.

The Russian wild card said: "It's great to get that major out of the way. It was an incredible opportunity. I'm very thankful for the opportunity."

Sharapova hadn't played in a major tournament since the Australian Open in January 2016, when she tested positive for the newly banned drug meldonium. She served a 15-month ban, returning to the tour this April with a ranking too low to get into Grand Slam events.

The French Open denied her a wild card invitation, then she planned to try to qualify for Wimbledon before pulling out because of an injured left leg. She was able to enter the US Open thanks to a wild card from the US Tennis Association.

Sevastova, who won the clash at 5-7, 6-4, 6-2 at the Arthur Ashe Stadium, will in quarterfinals take on American Sloane Stephens, who ousted Germany's Julia Goerges 6-3, 3-6, 6-1.

In men's actions, Sam Querrey of the United States eased past German Mischa Zverev 6-2, 6-2, 6-1 to reach quarterfinals and Diego Schwartzman of Argentina upset Lucas Pouille of France 7-6(3), 7-5, 2-6, 6-2 to also make last eight.

Kevin Anderson of South Africa and Pablo Carreno-Busta of Spain reached quarterfinals with hard fought wins.