Both of last year's Qatar TotalEnergies Open finalists picked up victories in Doha on Monday, as Garbiñe Muguruza of Spain and Petra Kvitova of the Czech Republic earned straight-sets wins.

No.5 seed Muguruza, the 2021 runner-up, survived a tough first set against Sorana Cirstea of Romania before easing to a 7-6(4), 6-1 second-round win in an hour and 27 minutes.

"I feel like I started slow, and she was playing very aggressively since the beginning," Muguruza said afterwards. "I had to bring something different, better energy, better game, so I did. I’m very happy that I was able to go through this tough match."

Stat corner: Muguruza improved her win-loss record against 31st-ranked Cirstea to 5-0, and 10-0 in sets. One of those victories came at Doha in 2018, and another came in the third round of 2017 Wimbledon, en route to Muguruza's second of her two Grand Slam titles.

Muguruza is now 13-6 in Doha throughout her career. The former World No.1 has twice reached the final, in 2018 and last year. In both of those finals, she was defeated by Kvitova.

Only four active players have more main-draw victories at this event than Muguruza's 13: Kvitova (21), Svetlana Kuznetsova (19), Victoria Azarenka (18) and Simona Halep (14).

Tale of the match: In their latest clash, Cirstea had seven more winners than Muguruza, but also 16 more unforced errors than the Spaniard. Cirstea converted both of her break points but was outnumbered by Muguruza, who broke the Romanian four times.

Cirstea garnered an early 3-0 lead in the first set, but Muguruza converted her fifth break point of the 4-2 game to pull back on serve. The pair moved into the tiebreak, where Muguruza fired some well-timed winners to lead 4-3. Muguruza forced errors from Cirstea the rest of the way to eke out the opener.

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Muguruza dropped serve in the opening game of the second set, but that would prove to be her final miscue as she reeled off the next six games to grab another win over Cirstea.

Next up: Muguruza, who became the first player to move into the round of 16, awaits the winner of Tuesday's second-round meeting between No.12 seed Victoria Azarenka of Belarus and Madison Brengle of the United States.

Kvitova bests Begu: Defending champion Kvitova, meanwhile, reversed a recent result as she swept past Irina-Camelia Begu of Romania 6-3, 6-1 in the first round.

Two-time Wimbledon champion Kvitova had been 5-0 against Begu through the start of this year, but Begu finally got her first win over Kvitova in St. Petersburg just two weeks ago, and in straight sets to boot.

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However, 21st-ranked Kvitova got back on track in their rivalry in Doha on Tuesday, knocking out World No.55 Begu in just 55 minutes. Kvitova won 82 percent of points behind her fearsome first serve and converted five of her six break points on the day.

Former World No.2 Kvitova will next face No.16 seed Elise Mertens of Belgium in the second round, after Mertens overcame Jasmine Paolini of Italy 6-3, 2-6, 7-5. Kvitova won her lone prior meeting against Mertens, in the 2018 Cincinnati quarterfinals.

Kontaveit cruises: No.4 seed Anett Kontaveit of Estonia joined Muguruza in the round of 16, after Kontaveit defeated Ana Konjuh of Croatia 6-2, 6-3 in an hour and 24 minutes.

World No.7 Kontaveit had to face 12 break points in the encounter, but fended off 10 of them to collect her second win in two meetings against 51st-ranked Konjuh.

The victory marks Kontaveit's 10th match-win of 2022, joining Simona Halep, Madison Keys, Ashleigh Barty and Jelena Ostapenko in the 10-win club for the year so far.

In the round of 16, Kontaveit will meet the winner of the aforementioned match between Kvitova and Mertens.