Novak Djokovic opened his bid for a first Olympic gold medal with a 6-0, 6-1 victory at Roland Garros that could set up a second-round matchup with longtime rival Rafael Nadal.
No. 2 seed Carlos Alcaraz of Spain, the reigning French Open and Wimbledon champion, also opened with an easy 6-3, 6-1 victory over Lebanon's Hady Habib.
Serbia's Djokovic, who is seeded No. 1 in the men's field after Jannik Sinner pulled out with tonsillitis, needed less than an hour to dismiss Australia's Matthew Ebden, a doubles player participating in a tour-level singles match for the first time in two years.
Ebden got into the singles bracket because he was in Paris to play doubles and thus available when 16th-ranked Holger Rune of Denmark withdrew with an injured wrist.
Ebden's lone game came after he was already down 6-0, 4-0 -- and he celebrated by pulling the front of his yellow shirt over his head and baring his chest to roars from the flag-dotted crowd.
Djokovic was less amused, saying he doesn't think someone like Ebden, a 36-year-old doubles player from Australia who hadn't competed in a tour-level, main-draw singles match since June 2022, should have been on the court without a teammate at the Summer Games.
"I really don't understand the rules. They're really not logical for me," Djokovic said. "I don't think it's a good image for the sport, to be honest. There were a lot of singles players that have plenty of time, that were alternates, that could have been called to come. This part I don't get."
Djokovic has endured some Olympic disappointments, twice losing in the semifinals, with his only medal being a singles bronze in Beijing in 2008. His win Saturday was his 14th at an Olympics -- the most for a man since tennis returned to the Summer Games in 1988.
Nadal, the Spaniard who won a record 14 of his 22 Grand Slam titles at the French Open and owns two Summer Games golds, is scheduled to play his opening singles match Sunday. He was a surprise torch-carrier during the rain-soaked opening ceremony along the Seine on Friday night.
"Playing him is like finals, in any tournament," Djokovic said of the potential matchup with Nadal. "Particularly here, knowing what he has achieved and what he's done for our sport, but particularly here at Roland-Garros, his record speaks for itself. I look forward to it. If we get to face each other, it's going to be possibly the last time we're going to face each other on a big stage. So I'm sure that people would enjoy it. I'm looking forward to it, and I'll be ready for that matchup."
Nadal and Alcaraz won the first match they have ever played together as a doubles team, eliminating Argentina's Maximo Gonzalez and Andres Molteni 7-6 (4), 6-4 on Saturday night.
Ebden was not the first doubles player asked to fill in, but he was the first to say yes.
"From the word go, I just had to make a joke of it," he said about taking on Djokovic, who has spent more weeks ranked No. 1 than anyone in tennis history. "I wasn't coming here to play singles, put it that way."
ITF spokeswoman Heather Bowler said the group devises the Olympic rules for the sport in conjunction with the International Olympic Committee. The cutoff for having an athlete on an Olympic roster for tennis is a week before the opening ceremony, which was Friday.
"We'd love to have last-minute replacements, but in the grand scheme of things, with 10,500 athletes and 206 National Olympic Committees (at the Games), it's logistically extremely difficult and there has to be a cutoff point for off-site replacement at some point," Bowler said. "Any change would need to be discussed with the tours" that run women's and men's professional tennis.
Day 1 of tennis began with showers that might have contributed to slow lines for umbrella-toting spectators at the facility's security checks near entrances and postponed by at least 4½ hours the start of matches at the 10 courts without retractable roofs.
ESPN's Coley Harvey, The Associated Press and Reuters contributed to this report.