LONDON — Carlos Alcaraz, locked in a five-set struggle at Centre Court, looked toward his coach Monday and shouted something about how Fabio Fognini — 38 years old, retiring after this season, winless in 2025 — looked as if he could keep playing until he’s 50.

“I don’t know why it’s his last Wimbledon,” Alcaraz said later, “because the level he has shown, he can still play three or four more years. Unbelievable.”

The two-time defending champion at the All England Club needed to go through more than 4 1/2 hours of back-and-forth shifts against the much-older and much-less-accomplished Fognini before emerging with a 7-5, 6-7 (5), 7-5, 2-6, 6-1 victory in the first round.

It wasn’t supposed to be that tough.

“Didn’t expect to play five sets against him,” Fognini said. “I had my chance.”

Consider, to begin with, that the No. 2-seeded Alcaraz is 22, already a five-time Grand Slam champion, including his latest at the French Open three weeks ago, and is currently on a career-best 19-match winning streak.

Consider, too, that Fognini has never been past the third round at the All England Club in 15 appearances and reached the quarterfinals at any major tournament just once — way back at the 2011 French Open. He entered Monday ranked 138th and 0-6 this year.

Oh, and then there’s this: Only twice has the reigning men’s champion at Wimbledon been beaten in the first round the following year, Lleyton Hewitt in 2003 and Manuel Santana in 1967.

There were times Monday when Alcaraz appeared to be something less than his best, far from the form he displayed during his epic five-set, 5 1/2-hour comeback victory over No. 1 Jannik Sinner for the championship at Roland-Garros.

Alcaraz double-faulted nine times. He faced a hard-to-believe 21 break points. He made more unforced errors, 62, than winners, 52.

“It doesn’t matter the winning streak that I have right now, that I’ve been playing great on grass, that I’ve been preparing really well,” said Alcaraz, who beat Novak Djokovic in the 2023 and 2024 finals. “Wimbledon is different. I could feel today that I was really nervous at the beginning.”

Next for Alcaraz will be a match Wednesday against Oliver Tarvet, a 21-year-old British qualifier who plays college tennis at the University of San Diego and is ranked 733rd.

Still, Alcaraz said: “I have to improve in the next round.”

Fognini — whose wife, 2015 U.S. Open champion Flavia Pennetta, held one of their children in the stands — is a self-described hothead and is known for mid-match flareups, including at Wimbledon, where he was fined $3,000 in 2019 for saying during a match that he wished “a bomb would explode at the club” and a then-record $27,500 in 2014 for a series of outbursts. He was put on a two-year probation by the Grand Slam Board in 2017 after insulting a female chair umpire at the U.S. Open and getting kicked out of that tournament.

Such behavior wasn’t displayed Monday.

While Alcaraz escaped, seven seeded men exited on Day 1, including 2021 runner-up Matteo Berrettini, No. 8 Holger Rune, No. 9 Daniil Medvedev — who also lost in the first round at the French Open — No. 16 Francisco Cerundolo, No. 20 Alexei Popyrin, No. 24 Stefanos Tsitsipas and No. 31 Tallon Griekspoor. No. 20 Jelena Ostapenko, the 2017 French Open champ, lost, while women’s winners included No. 1 Aryna Sabalenka, No. 6 Madison Keys, 2023 Wimbledon winner Marketa Vondrousova and 2021 U.S. Open champion Emma Raducanu.

Sabalenka beat 194th-ranked Carson Branstine, who was born in Irvine, 6-1, 7-5 in 73 minutes.