Top-seed Rafael Nadal has won through to the second round at of the US Open, beating a determined Teymuraz Gabashvili in straight sets on Tuesday.
The world No.1 could only break the Russian's serve in the third set - which he then did twice - sealing the win 7-6 (7-4) 7-6 (7-4) 6-3 in a tick under three hours.
Third seed Novak Djokovic struggled past close friend and countryman Viktor Troicki in five sets, 6-3 3-6 2-6 7-5 6-3.
Djokovic will face Germany's Philipp Petzschner in the second round after the world No.51 dispatched of Dusan Lojda in straight sets 6-3 6-1 6-1.
Frenchman Jeremy Chardy caused an upset at the US Open, beating 24th seed Ernests Gulbis in straight sets in the first round.
Chardy took the match in straight sets 6-2 7-6 (7-1) 6-4, and was one of six French men to win their way through to the second round on Tuesday.
The other five winners representing France were Julien Benneteau, Arnaud Clement, Benoit Paire, Adrian Mannarino and Florent Serra.
Chardy, the world No.64, equalled his personal-best effort at Flushing Meadows by making the second round and can better that record should he defeat Daniel Gimeno-Traver when the two clash on Thursday, after the Spaniard defeated Jarkko Nieminen in straight sets 7-6 (7-1) 6-4 6-3.
World No.152 Mannarino defeated Pere Riba in a fifth-set tiebreaker, holding off the Spaniard to win 3-6 6-1 6-4 4-6 7-6 (7-1).
Serra won through to the next round, beating Germany's Florian Mayer 7-5 6-2 6-0.
Benneteau upset 28th seed Czech Radek Stepanek 6-4 6-2 4-6 6-4 in their first round match on Tuesday, with the world No.37 hitting 23 aces on his way to victory.
Another seed ousted on day two was Cypriot 16th-seed Marcos Baghdatis, who fell to French veteran Clement in five sets.
Qualifier Paire held on to beat Germany's Rainer Schuettler in five sets after leading two sets to love.
The world no.163 held on to win 6-3 6-3 4-6 3-6 7-6 (7-2) in the biggest victory of his short career.
Paire will face Feliciano Lopez in the second round after the Spaniard defeated Santiago Giraldo 6-4 6-4 6-4.
Canadian qualifier Peter Polansky defied his world ranking of 205 to defeat 30th seed Juan Monaco in straight sets 6-2 7-6 (7-5) 6-3.
Tommy Robredo eased through to the second round with a straightforward victory over Lukas Rosol 6-4 6-3 6-1.
American Mardy Fish was pushed to five sets in his opening clash against Jan Hajek, but it was far from a close finale as the 19th seed ran out a 6-0 3-6 4-6 6-0 6-1 winner.
Fish will play Pablo Cuevas in the second round after the Uruguayan defeated Julio Silva in straight sets 7-6 (7-0) 6-1 6-2.
Benjamin Becker won an all-German first-round encounter, defeating Daniel Brands 7-6 (7-1) 7-6 (7-5) 6-4.
David Ferrer handled his opening match with ease, the 10th seed winning 6-2 6-2 6-3 over Alexandr Dolgopolov.
Eighth seed Fernando Verdasco snuck past Italian Fabio Fognini after an early scare, winning 1-6 7-5 6-1 4-6 6-3.
American James Blake coasted through to the second round, winning 6-3 6-2 6-4 over Kristof Vliegen.
Uzbekistan's Denis Istomin had a first-serve percentage of 49, but it made little difference in his straight-sets winner over Maximo Gonzalez.
Eduardo Schwank progessed to the next round with a four-set win over local hope Robby Ginepri.