Maria Sharapova came through the way she so often does in the crucible of a third set, beating 95th-ranked Alexandra Dulgheru of Romania 4-6, 6-3, 6-2 in the second round of the US Open.
Roger Federer claimed his 50th win of 2014 as the 17-time major winner got his campaign for a record sixth US Open off to a battling start.
Leander Paes and Sania Mirza won their respective doubles matches to advance to the second round of the US Open at the Flushing Meadows in New York.
Photo favourites Eugenie Bouchard and Ana Ivanovic eased into the US Open second round in New York on Tuesday.
Roger Federer has not won a Grand Slam title this year but the 17-time Grand Slam champion topped Forbes magazine's list of the 10 top tennis money-makers.
Novak Djokovic wasted no time in seeing off Argentinian challenger Diego Schwartzman as four former US Open champions reached the second round with varying degrees of difficulty.
Maria Sharapova found no room for sentiment on Monday to give her old friend Maria Kirilenko a tennis lesson and roll to a 6-4 6-0 win and into the second round of the US Open.
The evergreen Swiss may be carrying a bit more baggage these days, not least with his four children in tow, but in his 60th successive grand slam, the 33-year-old truly believes he can extend his record tally of singles titles to 18.
Murray outlasted Robin Haase 6-3, 7-6 (6), 1-6, 7-5 in the first round on Monday during an afternoon that was hot but not particularly humid.
World number one Novak Djokovic, seeking to consolidate his Wimbledon win, is one of four former champions in action Monday on the first day of the US Open.
Novak Djokovic has had indifferent results in the run-up to the US Open, but the world number one is not concerned. In fact, he is riding high as a newly-wed and a soon-to-be father.
Two-time champion John Isner withdrew from the US Open tune-up event at Winston-Salem on Thursday with a left ankle injury. It wasn't yet clear if the injury would affect his appearance in the US Open, which starts on Monday.
Reigning Wimbledon champion Petra Kvitova advanced to the semi-finals of the WTA New Haven hardcourt tournament on Thursday with a 6-4, 6-1 triumph over Czech compatriot Barbora Zahlavova Strycova.
Camila Giorgi sprang an upset to defeat four-time champion Caroline Wozniacki 6-4, 6-2 and reach the quarter-finals of the WTA Connecticut Open, a final warm-up for the US Open.
Reigning Wimbledon champion Novak Djokovic has been seeded number one for the US Open with five times winner Roger Federer seeded second, the United States Tennis Association announced on Tuesday.