Roger Federer overcame a brief scare to beat Indian qualifier Sumit Nagal in his first-round match at the US Open.
The 38-year-old Swiss, who is bidding for a record sixth title in New York, lost the first set before recovering to win 4-6 6-1 6-2 6-4.
Earlier on Monday, world number one Novak Djokovic progressed with a straight-sets victory over Spaniard Roberto Carballes Baena.
The Serb kicked off the defence of his title with a 6-4 6-1 6-4 win.
Djokovic, 32, has reached the final on his past three appearances in New York but was taken to four sets in his opening two rounds last year.
In the women’s draw Serena Williams made the perfect return to the US Open after last year’s controversial final by thrashing her long-time rival Maria Sharapova.
Williams, 37, won 6-1 6-1 in a first-round meeting which ended up lasting just 59 minutes.
Twelve months ago, Williams called the umpire “a cheat” and “a liar” during her loss to Naomi Osaka.