NEW YORK - Roland Garros champion Barbora Krejcikova held off a spirited comeback from former No.1 Garbiñe Muguruza, defeating the Spaniard 6-3, 7-6(4) to advance to her first US Open quarterfinal. The No.8 seed has now won 29 of her past 32 matches and tallied her fourth Top 10 win of the season to make her second major quarterfinal. She will face No.2 seed Aryna Sabalenka on Tuesday.

Krejcikova and Muguruza split their two previous meetings this season, with Muguruza prevailing in the Dubai final and the Krejcikova avenging the loss in the Round of 16 in Cincinnati three weeks ago, but this would be their first meeting at a Slam. Though now a major champion and Top 10 player, Krejcikova is making her main-draw singles debut at the US Open and this would be her first foray under the bright lights of Arthur Ashe Stadium.

In a match that pitted Muguruza's firepower against Krejcikova's craft, the Czech jumped into the driver's seat from the start, building a quick 3-0 lead with patiently crafted points that allowed her to control the rallies from the center of the court. But Muguruza told reporters after her hard-fought three-set win over Victoria Azarenka in the third round that she felt battle-tested coming into the second week, and those fighting qualities were on display as she continued to reel in Krejcikova. In back-to-back deuce games, Muguruza shortened the points to hold to 1-3, then break the Krejcikova serve with two forehand winners to get back on serve. 

Krejcikova, full of confidence from her protracted run of form, calmly reeled off the last three games of the set to take it 6-3 and then looked ready to race to the finish line in the second set, jumping out to a 4-0 lead. 

Turning Point: Two games from what would have been a short and clinical night for the Czech, Muguruza turned the tide. Finding more pace and depth and leaning on her own defensive skills, Muguruza began to wrench control of more baseline rallies. Krejcikova's backhand began to break down and Muguruza reeled off five consecutive games and earned three set points on Krejcikova's serve at 4-5. The Czech gamely saved all three and held with her 10th ace of the night, but went off court for a medical timeout before she was to serve at 5-6.

When the match resumed, Krejcikova held at love and played a clean tiebreak to win it 7-4 and close out the match after 1 hour and 54 minutes.

After the match, Krejcikova sat at her bench and appeared to struggle to catch her breath. After declining the post-match interview, she was eventually helped off court by the physio and tournament doctor.

"I think I started the match really well and was playing good tennis," Krejcikova said via quotes obtained by the WTA after the match. "The key was to start the match well. There were a lot breaks, which was difficult but I was happy that I won the first set 6-3. Out of nowhere I got the lead 4-0 and then things started to get complicated.

"Garbine started to raise her level and I was expecting that. At the end I was really struggling and I feel really bad right now. I don’t really know what happened but I couldn’t breathe. I started to feel dizzy and the whole world was shaking. It never happened to me before.

"I just gave my all at the end. It’s tough because it was my first time on such a big court playing the night session and I was really having fun until then." 

Stat of the Match: Krejcikova proved the more successful aggressor in the match, finishing with 29 winners to 28 unforced errors, compared to Muguruza's 20 winners to 24 unforced errors. 

Next up: Krejcikova will face Sabalenka in the quarterfinals. The Belarusian is the highest seed remaining in the tournament and moved through to her second straight Slam quarterfinal with a 6-4, 6-1 win over Elise Mertens. While Krejcikova and Sabalenka are familiar with each other's doubles games, having met three times, they have played just once in singles. That came in Linz last fall, where Sabalenka squeezed out a 7-5, 4-6, 6-3 win in the semifinals. 

"From what I remember I played Sabalenka last year in a three-setter," Krejcikova said. "She plays extremely well, she is really fit, and has a huge game. It’s going to be extremely difficult and I hope I can recover and be ready to play."