Rafael Nadal made a smooth start to his bid to capture the one grand slam title that has eluded him when he wore down Russia's Teymuraz Gabashvili 7-6 (4) 7-6 (4) 6-3 in the first round of the US Open on Tuesday at Arthur Ashe stadium.

Nadal had to dig deep to see off the stubborn Gabashvili after three hours of intense shot-making.

Neither player dropped serve in the opening two sets, but Nadal's superior big-match experience came through and he won both tiebreakers before Gabashvili finally cracked in the third set.

"I prefer to play one hour and 10 minutes," Nadal said. "Everybody wants to win easier.

"[When] you play against [lower-ranked] players they don't have much to lose, so they play aggressive. I had a difficult match, but I think I did play well."

Nadal's straight sets win capped another dramatic day when most of the results went according to the script, but not before some brutal contests for three former finalists on a sweltering hot day at Flushing Meadows.

Novak Djokovic dispelled his reputation as a quitter after battling through five gruelling sets, while Jelena Jan-kovic and Svetlana Kuz-netsova were pushed to the brink of exhaustion as temperatures soared to 35ºC.

World No3 Djokovic looked to be heading for an early exit when he fell two sets to one and a service break behind fellow Serb Viktor Troicki, but somehow summoned up the strength to fight back and win 6-3 3-6 2-6 7-5 6-3.

For most of his match, Djokovic was soaked in sweat and gasping for air and playing an opponent showing no signs of weariness.

It was only in the fifth set, when the sun began to set and Troicki started to wilt, that relief finally came.

Jankovic, a finalist in New York in 2008, beat Romanian Simona Halep 6-4 4-6 7-5 after Kuznetsova, champion in 2004 and runner-up in 2007, had to work overtime to beat Japan's Kimiko Date Krumm 6-2 4-6 6-1.

Under the tournament's extreme heat policy, players are allowed to request a 10-minute break between the second and third sets if the mercury exceeds 30ºC before the start of the match.

Kuznetsova's match, however, began before the policy was invoked. Maria Sharapova, the 2006 US Open champion, was also given a tough work-out from Australia's Jarmila Groth in their match, played at dusk in cool weather, before prevailing 4-6 6-3 6-1.

Vera Zvonareva had a much easier time against Slovakia's Zuzana Kucova on the Louis Armstrong stadium, winning 6-2 6-1.

The biggest casualty in the men's draw was Marcos Baghdatis of Cyprus, seeded 16th, while the highest women's seed to fall was China's Li Na, seeded eighth.

Denmark's Caroline Wozniacki, last year's runner-up and the top seed, did not begin her match until just before midnight local time because of the earlier backlog, but she made up for lost time by thumping American wild card Chelsey Gullickson 6-1 6-1 in just 61 minutes.