Roger Federer eased his way into the second round of the US Open following an impressive opening victory over Marinko Matosevic.
The five-time champion sealed victory in less than two and a half hours after beating his Australian opponent 6-3 6-4 7-6 (7-4) at the Arthur Ashe Stadium on Tuesday.
"Marinko has got a big game, I was never quite sure what to expect," Federer said following his victory. "I'm happy I came through. It was a bit more difficult than I thought it would be in the third set when I had a break. But it's always good to win tie-breaks."
Fourth seed David Ferrer also booked his place in the next round despite dropping a set to Damir Dzumhur of Bosnia-Herzegovina. The Spaniard recovered from his lapse of concentration in the third set however to seal an emphatic 6-1 6-2 2-6 6-2 victory.
In the women's singles, Serena Williams' quest to improve on a disappointing 2014 season got off to a bright start as she swept past Taylor Townsend. The defending champion took less than an hour to brush past her fellow American and seal a 6-3 6-1 victory at the Arthur Ashe Stadium.
However, Britain's Heather Watson's tournament was brought to a swift end after she was on the receiving end of a one-sided 6-1 5-1 thrashing to Sorana Cirstea of Romania.
The shock of the tournament so far came on Court 6 as 15-year-old American CiCi Bellis claimed a memorable 6-1 4-6 6-4 victory over 12th seed Dominika Cibulkova. The teenager, ranked 1208th in the world and only competing at Flushing Meadows by virtue of a wildcard place from winning the US girls' national championship, will face Zarbia Dyas of Kazakhstan in the next round.
"I'm feeling amazing," she said. "I'm still speechless. I'm still in shock about that match.
"I went into the match thinking it was going to be such a great experience, but I never thought I would come out on top winning."