MADRID, Spain - Volvo Car Open champion Kiki Bertens continues to work her magic on clay, moving from green to red at the Mutua Madrid Open to knocking out 2014 champion Maria Sharapova, 4-6, 6-2, 6-3.

"I’d never played [Sharapova], but of course when you see her play, you know that she’s hitting the ball so hard," Bertens said during her post-match press conference.

"I was a little bit struggling in the beginning, with trying to find the solution, like where I can play the higher balls," Bertens continued. "I think how long the match was, I managed to find a way in that, so I’m really proud of myself: that I worked myself into this match, and I could turn it around."

The big-hitting Dutchwoman has been a force on clay since 2016 when she rolled into her first Grand Slam semifinal at the French Open, and has been equally emphatic in Madrid, where she won the last 10 points of her upset win over reigning Australian Open champion Caroline Wozniacki.

"I didn’t play so well in the first set, and after yesterday, where I played so well, I was a little bit disappointed," said Bertens. "That was the most difficult part: to find my game again, and to play some longer rallies."

"I think in the beginning, I was going for my shots too much, and I was like, ‘Okay, just keep hanging in there, get as many balls back in the court, and try to find your game,’" the top-ranked Dutchwoman explained. "And I think that’s what I did, and that’s what I’m proud of."

Against Sharapova, Bertens shook off losing the opening set to take an immediate double break lead and leveled the match behind some impressive play from the baseline.

The 26-year-old broke first in the decider and while she couldn't serve out the match at 5-2, she duly broke right back to secure her first-ever Premier Mandatory semifinal after two hours and five mintues on Arantxa Sanchez Stadium.

For Sharapova, it was nonetheless an encouraging week that saw her win her first WTA main draw matches since the Australian Open and reach a Premier Mandatory quarterfinal for the first time since 2015.

"I think there are definitely a few that I can take away from this," she said after the match. "But I also look at these types of matches, I see a lot of things I should be better at, I should improve at. I think it's a combination of, yes, taking the positives, but also being a little tough on yourself and expecting a little bit more from yourself. That's the only way to improve. You can't keep giving yourself a pat on the back.

"Of course, it was great to get those wins against those few players. But there's a reason I came up short today. You want to also evaluate that and go back to the drawing board and start over again."

In all, Bertens balanced 21 winners to 34 unforced errors and converted seven of 12 break point opportunities, but the biggest difference came behind the first serve. Sharapova won just 53% of those points to Bertens' 70%.

Standing between her and the biggest final of her career is No.7 seed Caroline Garcia, who became the first into the final four on Thursday when she eased past hometown hero Carla Suárez Navarro in straight sets.