Top seed Iga Swiatek survived a gritty challenge from lucky loser Kamilla Rakhimova in the first round of the US Open, saving triple set points in the second-set tie-break before advancing 6-4, 7-6(6) in one hour and 52 minutes.

Early on, the first-time encounter threatened to be a one-sided rout after Swiatek raced out to a 4-0 lead for the loss of just three points. But thereafter Rakhimova, who took Aryna Sabalenka to three sets in Washington four weeks ago, pushed the Pole hard for the rest of the match.

Swiatek was unable to close out the world No.104 serving at 5-4 in the second set, and ultimately needed to squeak past in a tie-break that went down to the wire.

Australian Thanasi Kokkinakis shocked Stefanos Tsitsipas 7-6(5), 4-6, 6-3, 7-5 to achieve his best victory in a grand slam. It was an evenly-matched round and came as a big blow to the 11th-seeded Greek who came into the US Open after having a not-so-good North American tour.

On Monday, defending champion Coco Gauff overcame early nerves to cruise by France’s Varvara Gracheva 6-2, 6-0 in the first round.

Gauff was popular as ever with her home crowd as she sent 10 aces over on Arthur Ashe Stadium, showing her determination to put a string of frustrating performances behind her in New York.

“I was just trying to enjoy the match,” said Gauff, who set up a meeting with German Tatjana Maria in the next round.

There were early signs of trouble as Gauff had five double faults in the first set.

She had to fend off three break points to hold her serve in the second game but the world No. 3 found her footing from there, breaking her opponent’s serve in the third and seventh games.

Gracheva was never able to match Gauff’s firepower, with 25 unforced errors and just five winners, as the American broke her on the fourth try in the opening game of the second set. Gauff ploughed through the second set in 27 minutes, upping her level across the board as she produced only five unforced errors.

“It was definitely a lot of pressure, this tournament, but I’m just enjoying it,” said Gauff. “Whatever happens, happens.”

Gauff was not the only past US Open champions on Monday’s schedule: The night session began with 2017 winner Sloane Stephens blowing a huge lead against Clara Burel and losing 0-6, 7-5, 7-5 after taking the first nine games.

Iva Jovic, a 16-year-old from California, became the youngest American to win a women’s main-draw match at the US Open since 2000, eliminating 2023 Australian Open semi-finalist Magda Linette of Poland 6-4, 6-3.

Sabalenka prevails

Sabalenka opened her campaign with a 6-3, 6-3 win over qualifier Priscilla Hon, with the Belarusian fighting hard for every point in a dominant performance.

Sabalenka, who came up short in the final a year ago and reached the semis in 2021 and 2022, fired off 27 winners to set up a meeting with Italian Lucia Bronzetti.

“Even though I didn’t play my best tennis I was fighting for every point,” said Sabalenka, who arrived in New York in terrific form after winning in Cincinnati. “She played really aggressive, great tennis today. It wasn’t easy facing her in the first round.”

With the New York crowd on her side, the twice Australian Open winner used her lethal forehand to break Australian Hon in the opening game and converted on another chance to close out the first set.

After trading breaks, Sabalenka converted an opportunity with a backhand winner in the sixth game of the second set.

Hon had upped her level across the board, producing only one unforced error in the second set, but could not match Sabalenka’s firepower as she failed to convert on any of the five break point chances she had in the seventh game.

Among the men’s seeds who advanced on Monday were No. 6 Andrey Rublev, No. 8 Casper Ruud, the 2022 runner-up at Flushing Meadows, No. 9 Grigor Dimitrov and No. 12 Taylor Fritz.