LINZ, Austria (AP) Top-seeded Garbine Muguruza and defending champion Anastasia Pavlyuchenkova advanced to the quarterfinals of the Generali Ladies with straight-set wins on Thursday.

The French Open champion defeated Monica Niculescu of Romania 6-1, 6-1, while Pavlyuchenkova recovered from dropping 4-1 behind in the opening set to beat Kirsten Flipkens of Belgium 6-4, 7-6 (2).

Muguruza held off two break points in her opening service game then was in control of the match.

''This was maybe close to my best,'' the sixth-ranked Spaniard said.

Muguruza's next opponent is Viktorija Golubic of Switzerland, who defeated Julia Goerges of Germany 7-5, 6-4. Golubic saved a set point when Goerges served at 5-4 in the opening set.

Pavlyuchenkova next plays second-seeded Dominika Cibulkova of Slovakia, who defeated Annika Beck of Germany 6-1, 6-3.

''This is the best year of my career,'' said the 10th-ranked Cibulkova, who has won two titles and appeared in three more finals. ''It just feels great to be a consistent player.''

Earlier, Madison Keys advanced to the quarterfinals by defeating Misaki Doi of Japan 6-2, 6-0. Dominating throughout, the third-seeded American had five aces and avoided break points, while the 30th-ranked Doi won only 40 percent of the points on her serve.

Keys will next play French qualifier Oceane Dodin.