A pair of Wimbledon champions turned in impressive performances on the opening day of the U.S. Open.
Third-seeded Garbine Muguruza of Spain and No. 13 Petra Kvitova each won their first-round matches in straight sets Monday at Flushing Meadows, N.Y.
Muguruza, who knocked off Venus Williams in this year's Wimbledon final, dropped only three games in a dominant 6-3, 6-0 victory over Varvara Lepchenko of the United States.
Kvitova, a two-time Wimbledon champion, received a stern test before dispatching former world No. 1 Jelena Jankovic with a 7-5, 7-5 victory.
While Muguruza did not record an ace in her lopsided victory, she won 83 percent of her first-serve points and converted on five of six break-point chances to prevail in 63 minutes. She will face either Duan Yingying or qualifier Claire Liu in the second round.
Kvitova, the 2011 and 2014 Wimbledon champion, had to rally from a 2-0 deficit in the second set against Serbian Jankovic, a 2008 finalist at the U.S. Open.
Jankovic committed four of her six double faults in the second set and won fewer than 50 percent of her first-serve points in the set (13 of 27) to allow Kvitova to advance.
"We had a few tough battles in the past, and I'm just happy to get through this tricky match," said Kvitova, who next faces France's Alize Cornet, a 6-4, 6-4 win over Great Britain's Heather Watson.
No. 18 seed Caroline Garcia breezed through her opening match with a 6-0, 6-1 victory over Tereza Martincova of the Czech Republic, needing 57 minutes to reach the second round.
Other seeded players to advance with straight-set victories were No. 30 Julia Goerges of Germany and 31st-seeded Magdalena Rybarikova of Slovakia.
No. 24 seed Kiki Bertens of the Netherlands was not as fortunate, losing in straight sets to Greece's Maria Sakkari 6-3, 6-4, while 32nd seed Lauren Davis lost to fellow American Sofia Kenin.