Jannik Sinner and Iga Swiatek claim easy wins but 'mentally exhausted' Coco Gauff struggles

World number one Jannik Sinner began his bid for back-to-back US Open titles with an emphatic victory on Tuesday as women's draw favourite Iga Swiatek swept into the second round.

Italian star Sinner cruised to a 6-1, 6-1, 6-2 win over Czech world number 89 Vit Kopriva in just 97 minutes.

"It feels great to be back here. Obviously it's a very special tournament," said Sinner, who is attempting to become the first man to repeat at the US Open since Roger Federer won five in a row from 2004-2008.

Sinner, 24, faces Alexei Popyrin in the third round.

"I'm very happy that I'm healthy again," said Sinner, who was forced to retire from last week's Cincinnati Open final against Carlos Alcaraz.

"I have amazing memories. Every year is different. You come here starting this tournament hopefully in the best possible way, which I did," he added.

Sinner's fast start on the Arthur Ashe Stadium court was matched by Poland's Swiatek, who was similarly emphatic in a 6-1, 6-2 rout of Colombia's Emiliana Arango.

The 24-year-old from Poland was always in control against 84th-ranked Arango, overwhelming the Colombian with some powerful groundstrokes mixed with some deft work at the net.

The win makes Swiatek the first woman in history to win 65 consecutive WTA-level first round matches, surpassing Monica Seles' previous record of 64.

The six-time Grand Slam singles champion - a winner in New York in 2022 - will face the Netherlands' Suzan Lamens in the second round.

Yet while Sinner and Swiatek strolled into the second round, 2023 women's singles champion Coco Gauff was forced to claw her way past Australia's Ajla Tomljanovic in a gruelling late night battle that lasted just under three hours.

"It wasn't the best but I'm happy to get through to the next round," said Gauff, who admitted she had been drained by an unsettled build-up to the tournament.

Gauff, who won her second career Grand Slam at the French Open earlier this season, overhauled her coaching team on the eve of the US Open in an effort to revamp her service game.

"Honestly it's been really tough, mentally exhausting," Gauff said. "But I'm trying. It wasn't the best today, but it was an improvement on last week."

While Gauff laboured to victory, two-time former champion Naomi Osaka had no such difficulty in dispatching Belgium's Green Minnen 6-3, 6-4.

The Japanese former world number one revelled in returning to a venue that she regards as a home from home.

"Whenever I play here the atmosphere feels like home, and it is home for me," said Osaka, who is seeded 23rd and will next face American Hailey Baptiste.

In other women's draw results on Tuesday, Ukrainian 27th seed Marta Kostyuk took down Britain's Katie Boulter 6-4, 6-4. Eighth seed Amanda Anisimova of the US ousted Australia's Kimberly Birrell 6-3, 6-2.

Brazil's 18th seed Beatriz Haddad Maia advanced with a 6-3, 1-6, 6-1 win over Britain's Sonay Kartal.

Russian 13th seed Ekaterina Alexandrova brushed aside Latvia's Anastasija Sevastova 6-4, 6-1, but Diana Shnaider and Sofia Kenin were the rare seeds to fall.