PARIS — Garbiñe Muguruza’s career has flickered at times, but it is again burning bright at the French Open.
The quarterfinal win over Sharapova was Muguruza’s third straight-sets victory over a Grand Slam champion in this tournament. She defeated Svetlana Kuznetsova in the first round and Samantha Stosur in the third round.
In Thursday’s semifinals, Muguruza will play top-ranked Simona Halep, who is still seeking her first major title. The No. 1 ranking will be up for grabs in their match. The other semifinal will feature a pair of Americans, No. 13 seed Madison Keys and 10th-seeded Sloane Stephens.
Halep booked her spot in the semifinal with a 6-7 (2), 6-3, 6-2 win over Angelique Kerber. It was a rematch of Halep’s three-set win over Kerber in the Australian Open semifinals in January, one of the best matches of the year.
In Paris, Halep used her greater comfort on the slow clay courts to her advantage, prevailing in most of the longest rallies.
“It’s tough against her, but it’s even nicer and better after I win a match against her,” Halep said of Kerber. “Shows me that I have enough patience, I have enough power inside to stay calm and just to play what I have to play against her.”
Halep has achieved the top spot in the rankings through consistency. She has won only one title in the past 12 months, at a small tournament in Shenzhen, China, but she has reached the quarterfinals or better 14 times.
Muguruza’s bid for the top spot is built on bursts of big-stage brilliance.
Since the beginning of the 2016 French Open, where she earned her first major title, Muguruza has a 32-6 record in Grand Slam singles matches. That includes a run to the 2017 Wimbledon championship. At regular tour events in that time, she has won only 61.1 percent of her matches, a 55-35 record.
Encouraged by her Australian coach Darren Cahill, Halep has been worked on remaining positive and optimistic, no matter the circumstances of a match. She pledged to “keep smiling” no matter the result of their semifinal.
“I have also no expectations, no pressure,” said Halep, who lost in the finals of last year’s French Open and this year’s Australian Open. “I just want to play as I did today, and as I did every day. If I do that, I will be OK after the match, no matter the result.”
Muguruza’s moods are more turbulent, but her coach, Sam Sumyk, said he knows how to read them.
“I kind of know, when I see her face in the morning, which Garbiñe to expect,” he said.
While Halep is focused on enjoying her tennis, Sumyk looks for the opposite in his player.
“When she’s suffering inside, I know it’s good,” he said of Muguruza. “I know it sounds weird, but yeah — suffering is not a negative thing. I know when she’s very demanding with herself and it’s never good enough, then it’s good.”
The dynamic between Sumyk and Muguruza appears more abrasive than most player-coach relationships on tour. His on-court coaching visits, which are allowed at WTA Tour events but not at Grand Slams tournaments, often grow tense.
“It’s a very anxious daily job,” Sumyk said. “It’s in front of everybody’s eyes. You’re judged constantly.”
Sumyk said he does not try to ease that nervous energy, which he believes “comes with the job.”
“I don’t try to make her more relaxed,” he said. “I try to make her understand what anxiety is, where it comes from, how to channel it. That’s what I try to do.”
Muguruza’s emotions took center stage at Roland Garros last year after she lost a fourth-round match to Kristina Mladenovic of France in front of a raucous, partisan crowd. At her post-match news conference, Muguruza broke down in tears and left the room for several minutes to regain her composure.
The moment, which the tournament included in a highlight reel used at this year’s draw ceremony, surprised Muguruza.
“I was surprised the next day when I saw a few headlines saying ‘Breakdown,’ ‘Tears,'” she said at a round-table interview last August. “I’m like, it’s not a breakdown! I’m just sad that I lost a hard match, and had a lot of emotion in that match.
“I wanted to show that I’m human. I’m not a robot. It’s true, because I feel like sometimes players are like ice, and I’m not ice. It doesn’t show that I’m weaker because I showed my feelings.”
Sumyk said they tried to learn how to better manage the emotional toll.
“We tried to analyze all these emotions at the end, once she was out of the tournament,” Sumyk said. “Where that comes from, why all of the sudden you kind of let it out — and actually, why she didn’t do it earlier. Because that could have actually helped her, to let go a little bit of some of that nerves. But she’d hold it, hold it, hold it, and then it happens after a defeat.”
Muguruza’s resilience manifested quickly; she won Wimbledon a month later. At that tournament, she was coached by Conchita Martinez, the 1994 Wimbledon champion, while Sumyk stayed at home for the birth of a child. Muguruza seemed to be more tranquil under Martinez’s guidance.
“I feel Conchita might be a little bit more easygoing,” Muguruza said Wednesday. “She understands sometimes more the player view. I think Sam is more strict, and a lot of energy out there.”
Martinez worked with Muguruza at a handful of other tournaments but she ended her partnership in April, leaving Sumyk again as Muguruza’s lone coach.
Sumyk admitted that the intensity he stokes could cause Muguruza to flame out at some point, though he believes it would be well in the future.
“Maybe in 10 years, if she keeps going like this, maybe she will feel burnt out,” he said. “But for now, she’s fine.”
This article originally appeared in The New York Times.