NEW YORK // Andy Murray became the first man through to the third round of the US Open with a straightforward victory over Croatian Ivan Dodig.
The third seed had been a little off colour in his first round match against Alex Bogomolov even though the scoreline was comfortable and tonight's performance was certainly an improvement.
Murray, who next faces either Feliciano Lopez or fellow Spaniard Pablo Andujar, broke the Dodig serve six times in total on his way to a 6-2 6-1 6-3 victory.
The Scot was happy with his performance, saying: "I thought I played well. There were a lot of long rallies. I moved my feet pretty well tonight, played well."
Murray had lost his opening two service games on Monday but it was a different story as he immediately threatened the Dodig serve, and raced to victory in an hour and 51 minutes.
Reigning Wimbledon champion and US Open 14-time Grand Slam champion Serena Williams sparked injury fears after turning her left ankle during a doubles match alongside her sister Venus.
There was no immediate indication regarding the extent of the injury from Williams but she was treated twice for the injury and played with a bandage on her ankle after trainers examined it.
While it was a setback, the Olympic gold-medal US duo cruised past compatriots Lindsay Lee-Waters and Megan Moulton-Levy 6-4, 6-0 in 63 minutes to reach the second round of the women's doubles tournament.
Serena will face Spain's Maria Jose Martinez Sanchez in the women's singles second round later today.
World No. 1 Victoria Azarenka, this year's Australian Open champion, reached the third round while defending champion Samantha Stosur and third seed Maria Sharapova, the reigning French Open champion, advanced with ease as well.
Spanish fourth seed David Ferrer, Argentine seventh seed Juan Martín del Potro and US ninth seed John Isner won their openers on the Flushing Meadows hard courts.
The US Open saw nine men's comeback triumphs from two sets down in the first round, matching the record from 1989, including Serbian ninth seed Janko Tipsarevic's 4-6, 3-6, 6-2, 6-3, 6-2 victory over Frenchman Guillaume Rufin.
And Australian Lleyton Hewitt, the 2001 US Open champion, reached the second round by dispatching Germany's Tobias Kamke 4-6, 6-2, 6-1, 6-4.
Reigning Australian Open champion Azarenka reached the third round by defeating Belgian qualifier Kirsten Flipkens 6-2, 6-2 in only 65 minutes for her 50th match victory of the year.
"I'm proud of everything I have achieved this season," she said. "It has been a great year."
Azarenka, who has reached the last eight in every Grand Slam event except the US Open, will next face Chinese 28th seed Zheng Jie.
Australian seventh seed Stosur took an hour to beat Romanian qualifier Edina Gallovits-Hall 6-3, 6-0 to reach a third-round date with US 31st seed Varvara Lepchenko.
Russian third seed Sharapova ripped Spain's Lourdes Dominguez Lino 6-0, 6-1 to book a third-round match against 21-year-old US wild card Mallory Burdette, ranked 252nd, who advanced with a 6-2, 6-4 victory over Czech Lucie Hradecka.
Ferrer, whose best Grand Slam showing was a 2007 US Open semi-final run, beat South African Kevin Anderson 6-4, 6-2, 7-6 (7/3) to reach a second-round match against Dutch qualifier Igor Sijsling.
Isner, the top American hope to end a nine-year US men's Grand Slam title drought, struggled to subdue Xavier Malisse 6-3, 7-6 (7/5), 5-7, 7-6 (11/9).
Del Potro, the 2009 US Open winner, advanced over France's Florent Serra 6-4, 7-6 (7/4), 6-4.