Murray, who won the men's singles title at Flushing Meadows in 2012, triumphed in the first match of the day on the main Arthur Ashe Stadium Court, as he overcame Nishioka in a match that lasted four hours and 39 minutes.

Nishioka won the first two sets 6-4 before Murray took sets three and four in tiebreaks 7-6 7-6.

Murray completed the fightback by winning the fifth set 6-4, in what was his first singles match at a Grand Slam since the 2019 Australian Open.

Since then, Murray has undergone hip surgery, and following the epic win over Nishioka, he faces Canadian Felix Auger-Aliassime in the second round.

In other men's matches during the day session, second seed Dominic Thiem benefited from a retirement as his opponent Jaume Munar pulled out when trailing by two sets.

The Austrian was leading 7-6 6-3 when Spaniard Munar retired.

Other men's seeds to triumph included Russia's Andrey Rublev, the tenth seed, who beat France's Jeremy Chardy 6-4 6-4 6-3, 2014 champion Marin Cilic, seeded 30th this year, who battled back from two sets down to beat American Denis Kudla 6-7 3-6 7-5 7-5 6-3 and 11th seed Karen Khachanov of Russia who was also taken the distance before he won 3-6 6-7 6-2 6-0 7-6 against Italy's Jannik Sinner.

In the women's draw, third seed Serena Williams beat compatriot Kristie Ahn 7-5 6-3, as she successfully started her quest to win a 24th Grand Slam, which would put her level with current all-time female Grand Slam holder Margaret Court.

Other women's seeds to win during the day session on the second day included tenth seed Garbine Muguruza of Spain who won 6-4 6-4 against Japan's Nao Hibino and ninth seed Johanna Konta of Britain who beat compatriot Heather Watson 7-6 6-1.

Two American top ten seeds were also victorious - second seed Sofia Kenin won 6-2 6-2 against Belgium's Yanina Wickmayer while seventh seed Madison Keys beat Hungary's Timea Babos 6-1 6-1.