New York: Another milestone looms for Roger Federer at the US Open on Thursday.

If the Swiss master wins his second round clash with Israel's Dudi Sela, he will chalk up his 225th grand slam win.

That will move him into outright second place among men, one clear of Andre Agassi, and closer to Jimmy Connors's record of 233, which Federer should surpass next year.

But first he has to beat Sela. "He's a talented little guy," Federer said. "He really works well with his height. That's why you have to be careful that you don't underestimate a player like that."

World number one Novak Djokovic can also edge closer to one of the sport's great records if he wins his clash with Carlos Berlocq of Argentina.

The Serbian is on one of the hottest streaks in tennis and has compiled a 58-2 record this season. The record for the most wins in a single season is 82, held by John McEnroe.

"This year has been tremendous, best so far in my career, and there has been a lot of talks about history-making and this incredible run," Djokovic said.

"I'm extremely honored and privileged to be part of the elite of the players that have made the history of the sport but my main focus is on the court."

Serena Williams will play her second round match against Michaella Krajicek of the Netherlands, flying the family flag alone after the surprise withdrawal of her sister.

The women's draw has been depleted by high-profile casualties, leaving Williams as the favourite, ahead of world number one Caroline Wozniacki.

But the Dane was in great form in her first outing at Flushing Meadows and also tackles a Dutchwoman in the next round on Thursday in Arantxa Rus.