Jessica Pegula, Daniil Medvedev and Marta Kostyuk among the early winners at the US Open

NEW YORK (AP) — Jessica Pegula was one of the first players to compete at the U.S. Open, and she learned last year that starting Sunday provided some nice relief.

“It is a little bit weird, but I did kind of enjoy that I could breathe for the next couple of days and everyone else is still freaking out about whether they’re going to win their first round,” she said.

The head start is great — unless it's a head start back to the airport.

“We were just talking about it, and I said, it’s so nice to play on Sunday when you win. But if you lose it’s not nice, because you feel like the tournament didn’t even start and you’re out of it,” No. 11 seed Marta Kostyuk said.

Pegula and Kostyuk both won easily and now the get the benefit of any extra day of rest before returning for the second round.

The No. 3-seeded Pegula beat Elena-Gabriela Ruse 6-3, 6-2. She said she was nervous early, which makes sense given what could be at stake for the 2024 U.S. Open runner-up.

Pegula leads the women’s tour with 46 wins this season. She has two titles and has reached three other finals. Pegula can become No. 1 in the rankings if she wins her first major title and No. 2 Elena Rybakina loses before the semifinals.

Pegula next faces the winner of the match between Venus Williams and fellow wild card Sofia Kenin. They were set to play in the nightcap at Arthur Ashe Stadium, and Williams and sister Serena are scheduled to play doubles together.

“I felt really nervous before I went out there, but I know my coaches were like, ‘You didn’t really look that nervous. We thought you played great,’” Pegula said.

The No. 11-seeded Kostyuk sure did, beating Storm Hunter 6-4, 6-1 for a strong start to the year's final major after reaching the semifinals at the French Open and Wimbledon.

It was the second year of a Sunday start, though some of the biggest headliners don’t begin until Monday. Two-time defending champion Aryna Sabalenka plays her opening match against Camila Osorio, before Carlos Alcaraz , who won his second U.S. Open title last year, plays his first singles match since April after recovering from a right wrist injury.

Past U.S. Open champions Naomi Osaka, Iga Swiatek, Sloane Stephens and Stan Wawrinka are also on the Monday schedule, along with Wimbledon women’s champion Linda Noskova and men’s contenders such as Ben Shelton, Arthur Fils, Felix Auger-Aliassime and Frances Tiafoe.

Daniil Medvedev, the 2021 U.S. Open champion, shook off his miserable preparation for the tournament by beating Hugo Gaston 6-4, 6-2, 6-4. The No. 7 seed was just 1-3 in the North American hard-court swing, usually a time he thrives.

“Last couple of weeks was not easy,” Medvedev said. “But I’m happy that today I managed to produce high-level tennis.”

Other winners Sunday included No. 19 Jasmine Paolini and No. 31 Leylah Fernandez, the 2021 U.S. Open runner-up. No. 27 seed Barbora Krejcikova, a two-time Grand Slam singles champion, lost 7-6 (4), 6-2 to Kamilla Rakhimova.

American Tommy Paul, the No. 20 seed, bounced back from losing a first-set tiebreak to Coleman Wong to win 6-7 (3), 6-1, 6-3, 6-3. Wong a year ago became the first man from Hong Kong to win an Open-era Grand Slam men’s singles match on the way to reaching the round of 32.

Novak Djokovic begins his quest for a record-extending 25th Grand Slam title on Sunday night against Mariano Navone. Djokovic, 39, most recently lost his opening match earlier this month at Cincinnati.

Maric Cilic, the 2014 U.S. Open champion, and 2022 runner-up Casper Ruud both withdrew with injuries on the opening day.

Though the main draws didn't begin until Sunday, action at the U.S. Open has already been going on for nearly a week. Large crowds gathered for the mixed doubles tournament , an exhibition headlined by Roger Federer's return to Flushing Meadows and the singles qualifying tournaments, with admission to the grounds free.

Fans who came for the first time Sunday may have noticed a tournament in transition. The U.S. Open is in the second year of a three-year renovation of Arthur Ashe Stadium, the main venue at the USTA Billie Jean King National Tennis Center. The improvements in the $800 million project include the addition of some lower-level seating, upgrades and additions of entertainment areas and the construction of a player performance center.

“Please pardon our appearance while we are reimagining spectacular,” reads a sign above the entrance to Ashe.

The project is scheduled to be completed in time for the 2027 U.S. Open.

See AP’s full tennis coverage here