WIMBLEDON, England — For Cori Gauff, 15, and Felix Auger-Aliassime, 18, Monday at Wimbledon was a day for teenage dreams coming true after their first victories at a Grand Slam tournament.

But established stars only slightly older seemed to treat first-round losses like midlife crises.

Naomi Osaka, 21, lost in the first round for only the second time in 14 Grand Slam main draw appearances.

After becoming the first player in more than a decade to win her first two Grand Slam titles consecutively, at last year’s United States Open and this year’s Australian Open, she has lost in the first week of the next two.

After a third-round loss last month at the French Open, the second-seeded Osaka fell to Yulia Putintseva, 7-6 (4), 6-2, in the first round of Wimbledon on Monday afternoon on Centre Court.

Later Monday, the sixth-seeded Alexander Zverev, 22, lost in four sets to the qualifier Jiri Vesely. The seventh-seeded Stefanos Tsitsipas, 20, lost in five sets to Thomas Fabbiano after saving match points in a fourth-set tiebreaker.

[Read about 15-year-old Cori Gauff’s victory over Venus Williams.]

All three demonstrated their devastation when they made it to the interview room.

Osaka, still wearing her match outfit and visor, was despondent in the news conference that began about 30 minutes after her loss, giving short and sullen answers.

“There’s answers to questions that you guys ask that I still haven’t figured out yet,” she said, softly.

Osaka did not blame her split with her coach Sascha Bajin in February; she was 9-1 this year with him and is 13-7 since they stopped working together.

Though an upset on paper, the result was not unexpected: Putintseva, a Muscovite who switched her representation to Kazakhstan, had beaten Osaka in their two previous meetings, last year in Hobart, Australia, and two weeks ago in Birmingham, England.

The hard-fought first set lasted exactly one hour, with Putintseva coming back from an early 1-3 deficit before ultimately winning a tiebreaker on an Osaka backhand that veered wide.

Putintseva broke Osaka’s serve in the fifth game of the second set with a successful drop-shot return winner, which she correctly challenged, allowing the Hawkeye review system to show it nicked the line. She won the next three games to close out the match.

Putintseva kept Osaka off-balance with a butcher’s block worth of knifing slices; “trying to make it as uncomfortable for her as possible” had been her game plan while weathering Osaka’s awesome power, Putintseva said.

“You have to stay cool,” she added. “Sometimes when she does an unbelievable winner, you have to accept it.”

Osaka is something of a hardcourt specialist, having never reached the fourth round at either the French Open or Wimbledon. She has won only 56 percent of her career matches on grass, and 57 percent on clay.

Osaka still struggled to handle the defeat, turning to the tournament moderator for mercy during a question about her new status as “a global superstar” and the incumbent challenges that come with it.

“Can I leave?” Osaka asked. “I feel like I’m about to cry.”

Tsitsipas, who lost to 89th-ranked Fabbiano, 6-4, 3-6, 6-4, 6-7(8), 6-3, came into Monday already feeling bad about himself, excoriating himself for showing his temper on the practice courts Sunday.

“I stepped on my racket, which made me feel horrible,” he said.

Fabbiano had a strong Wimbledon run last year, upsetting Stan Wawrinka in the second round in straight sets. That run came to a halt with a 6-2, 6-1, 6-4 loss to Tsitsipas.

Tsitsipas said he had trouble coping with Fabbiano’s improved forehand, which left Tsitsipas guessing throughout the match. He also did not rule out that his five-set loss to Wawrinka at the French Open in June might still be lingering in his psyche.

“It was very, very difficult to overcome that match,” Tsitsipas said. “I was really disappointed; I am disappointed now. People expected things from me; I didn’t deliver.

“When you get so much support, so much energy, so much positivity from everyone, then just ruin everything by yourself, it’s devastating.”

Though ranked 124th, Vesely has a strong pedigree at Wimbledon, having upset five seeded players in the last five years before beating Zverev, 4-6, 6-3, 6-2, 7-5.

Such context was scant consolation to Zverev, whose performances at the four Grand Slam events have often underpaced his stellar achievements at tour stops. He called Monday’s loss to Vesely “kind of a typical Grand Slam match for me,” and said it came down to his failure to perform his best on crucial points.

“I didn’t lose this match on tennis,” Zverev said. “It’s just, yeah, my confidence is below zero right now.”

Zverev has been distracted this year by a legal battle with his former manager Patricio Apey. He expressed feelings of betrayal toward Apey, whom he believed had tried to derail him on the eve of Wimbledon, describing “two really rough days” without being able to go into further detail because of the ongoing litigation.

“He does it on purpose right before a tournament like this, and I don’t know why he’s doing it,” an emotional Zverev told German reporters.

“It hurts me,” he added. “He was a man who was very close to me. I thought we were close, not only because of the job. I thought we were friends. But now he’s doing things I can’t understand.”

Zverev bleakly said his next step after Wimbledon was a destination unknown.

“I’ll take a few days off now,” he said, “and go somewhere where nobody can find me.”