Australian Ashleigh Barty's fine form in the lead-up to the French Open has continued with a 10th consecutive victory.
The world No.9 defeated American Danielle Collins 6-1, 1-6, 6-1 to advance to the third round of the Madrid Open for the first time.
Replay
Barty has taken to the red clay in the Spanish capital in her first tournament since claiming the Miami Open for the biggest title of her career in late March and winning all three of her matches in the Fed Cup semi-final, including both singles.
After dominating the first set against Collins, Barty found herself in trouble in the second before she rallied to close out Tuesday's (AEST) match in an hour and 25 minutes.
Barty blasted 18 winners but threw in 19 unforced errors during the topsy-turvy encounter.
The 23-year-old fired five aces but only made 55 per cent of her first serves while she converted four of eight break-point chances.
Barty applied heavy pressure from the start, reeling off five games in a row to put Collins, who has only three WTA main draw wins on red clay, on the back foot.
Collins responded by taking the last five games of the second set to level up the match.
But Barty regrouped and quickly rallied to a 3-0 lead before the world No.30 Collins got on the board in the final set.
The Australian No.1 continued her run by reeling off the final three games to set up a round of 16 showdown with Zazakh Yulia Putintseva, who beat Pauline Parmentier 6-4, 4-6, 6-3.
Defending champion Petra Kvitova defeated 2017 finalist Kristina Mladenovic 6-3, 7-6 (7-5) in her bid for a fourth title in the Spanish capital.
The second-seeded Kvitova outlasted Mladenovic by winning the last three points in the tiebreaker to close out the match in nearly two hours.
"I'm glad I won the tiebreak. That is my kind of issue sometimes, but overall it was pretty tight," Kvitova said.
"I fought hard in the end."
Seventh-seeded Kiki Bertens defeated Jelena Ostapenko 6-4, 6-3 to remain on track for a second-straight final in Madrid while eighth-seeded Sloane Stephens got past Victoria Azarenka 6-4, 2-6, 6-2.
Others to progress to the round of 16 were 12th-seeded Anastasija Sevastova, Belinda Bencic and Viktoria Kuzmova.