Roger Federer, oozing the confidence of a grand slam champion, opened his US Open campaign yesterday with a win over a cramping Jose Acasuso. The Argentine retired from the first-round match while trailing the Wimbledon champion 5-7, 6-3, 6-3, 2-0.

''I was already winning at that stage,'' said Federer, heading off suggestions he had been fortunate.

Federer swiftly recovered from a stuttering start to impose himself on Acasuso, who had won just one match since April and suffered first-round exits in six of seven previous events. But the Argentine offered plenty of fight on his way to taking the opening set.

However, there was never a hint of panic from the stylish Federer. The Swiss serve and volleyer calmly settled into the match and slowly took control.

His victim in the Wimbledon final, Mark Philippoussis, was also in form, beating Janko Tipsarevic 6-2, 7-6, 6-4.

''The first one is always the toughest,'' said Federer. ''There were a lot of nerves.''

Meanwhile, Tim Henman, who was beaten 6-3, 7-6 (7-2), 6-3 by Andy Roddick in the first round, described the American as ''the leader in the world game right now''.

Henman went into the contest on the back of a win over Roddick en route to taking the Legg Mason Classic in Washington DC recently, but this time he found the 20-year-old American, who has since won back-to-back Masters Series events in Montreal and Cincinnati, too quick and too powerful.

''I'm not going to serve like Andy,'' said Henman. ''You know, he's probably the best server in the game right now. But the way he mixed it up, he's got the pace behind his serve. But he's serving very smart. That's something that we can all learn from.''

In the women's singles, ninth seed Daniela Hantuchova survived a late scare against Russia's Julia Vakulenko before winning 6-0, 7-6 in an edgy contest.

''I am just so glad I could get through that match,'' she smiled as she walked off court. ''I lost a little bit my rhythm in the second set, so I am definitely relieved.''

She will next meet Tamarine Tanasugarn, who ousted Patty Schnyder, the No.18 seed, 6-4, 6-3.