?Andy Murray of Britain returns a ball to Lukas Lacko of Slovakia during the men's singles first round match at the U.S. Open tennis tournament in New York, the United States, on Sept. 1, 2010. Murray won 3-0. [Xinhua/Shen Hong]

Andy Murray advanced into second round in straight sets at the U.S. Open, where 10th-seeded Victoria Azarenka collapsed on court in the sweltering Flushing Meadow heat on Wednesday.

Sam Querrey, the men's 20th seed from the United States, beat another American, Bradley Klahn. A third U.S. player, 220th-ranked qualifier Ryan Harrison, upset 15th-seeded Ivan Ljubicic of Croatia.

Murray beat Lukas Lacko of Slovakia on the Arthur Ashe Stadium court, winning 6-3, 6-2, 6-2. The number 4 seed from Britain is trying to capture his first Grand Slam title.

Murray had 37 winners in the match, 17 more than Lacko. He'll face Jamaicas Dustin Brown, who outlasted Spain's Ruben Ramirez Hidalgo in straight sets, 6-4 7-6 (8-6) 7-5, in the second round.

Azarenka, from Belarus, collapsed on court in her match with Gisela Dulko of Argentina. Azarenka was trailing 5-1. She was taken off the court in a wheelchair and then by ambulance to a hospital for tests.

The British number one produced his full repertoire of shots as he wrapped things up in under two hours.

Murray must be delighted knowing the toughest player in his quarter, Tomas Berdych, has been eliminated.

Murray, who reached the US Open final in 2008, never looked in any danger as he comfortably saw off the threat of Lacko, who was making his tournament debut.

"I managed to get through in straight sets so I'm pleased, but it was a lot tougher than the score suggests," said Murray.

"Everyone in my box always tells me it's a lot tougher watching in the heat than playing but I'm not so sure. They were brutal conditions."

Murray broke Lacko in the fourth game of the first set and held through to claim the set in 38 minutes, although he dropped three set points, netting a drop shot, sending a forehand smash well long and watching a Lacko forehand volley winner before Lacko sent a forehand wide to finally give Murray the set.

Murray and Lacko exchanged breaks to begin the second set but Murray broke again in the third and seventh games to claim the set.

Lacko double-faulted away a break in the third game of the third set and Murray powered home with ease.

Lacko's best chance seemed to be at the start of the second set when he produced an outrageous shot with his back to the net to help him break back at 1-1.