NEW YORK (AFP) — Top seeds Jannik Sinner and Iga Swiatek survived US Open first round wobbles on Tuesday as two-time champion Naomi Osaka made a tearful and colorful return to Flushing Meadows.

Sinner fought back from a set and break down to defeat Mackenzie McDonald in his first match since being embroiled in a doping test controversy.

Fellow world No. 1 and 2022 US Open champion Swiatek saw off 104th-ranked Kamilla Rakhimova but only after having to save three set points in the second set.

Italian Sinner battled to a 2-6, 6-2, 6-1, 6-2 win over his 140th-ranked opponent on Arthur Ashe Stadium, racing away with 18 of the last 22 games.

Meanwhile, Carlos Alcaraz roared home for a 6-2, 4-6, 6-3, 6-1 victory over 186th-ranked Australian Li Tu to launch his bid to add the US Open to the Roland Garros and Wimbledon titles he claimed this year.

The 21-year-old Spaniard pushed his Grand Slam winning streak to 15 matches as he tries to join Rod Laver and Rafael Nadal as the only men in the modern era to win the French Open, Wimbledon and the US Open in the same year.

On the other hand, the 23-year-old Sinner was returning to action just a week after it was revealed he had failed two drug tests in March.

However, he escaped a lengthy ban from the sport when officials decided he wasn’t at fault for the presence of banned anabolic agent clostebol in his system.

“I was a little bit not in the best way,” Sinner said of his victory.

“The first match is not easy. He played really well in the beginning so I just tried to stay there mentally and find some rhythm to keep going.”

French Open champion Swiatek, chasing a second New York title to add to her four triumphs in Paris, saw off Russian lucky loser Rakhimova 6-4, 7-6 (8/6) to extend her season-leading record to 54 match wins.

However, it was an unconvincing display by the Pole who committed 41 unforced errors and had to fight off three set points in the second set.

“I try to adapt to the court and feel how it is,” Swiatek said.

“I’ll take it day by day to get more rhythm. It’s the biggest stadium we have and you feel it’s a huge deal.”

Osaka, who missed last year’s tournament after giving birth to her daughter Shai, stunned 10th seed Jelena Ostapenko.

Former world No. 1 Osaka, now ranked 88, came through 6-3, 6-2 for her first top 10 win in four years.

The Japanese star crunched nine aces in her 19 winners and committed just five unforced errors to her opponent’s 21.

Her tennis was as striking as her outfit. Osaka arrived in court with a brightly-coloured, giant bow on the back of her jacket and a frilly skirt over her playing dress.

To complete the ensemble, the 26-year-old attached small bows to the heels of both shoes.

“Last year I was watching Coco (Gauff) play and I so badly wanted to step on these courts again,” said a tearful Osaka, a four-time major winner.

“I didn’t know if I could just win this match and just to be in this atmosphere means so much to me.”

Osaka’s fellow tennis mum Caroline Wozniacki, runner-up to Serena Williams 10 years ago, needed just 53 minutes to see off Japan’s Nao Hibino 6-0, 6-1.

Daniil Medvedev, the Russian fifth seed who shattered Novak Djokovic’s dream of a rare calendar Grand Slam by claiming the 2021 US Open, went through with a four-set victory over Dujan Lajovic of Serbia.