By Steve Ginsburg

NEW YORK (Reuters) - Twice defending champion Roger Federer served his way into the third round of the U.S. Open with a workmanlike 6-3 6-4 7-5 victory over Briton Tim Henman on Friday.

Top seeded Federer fired only six aces and had his serve broken once but proved to be in a different league to Henman on Arthur Ashe Stadium.

The 25-year-old Federer, who has not lost a set in his two matches, will face either American Vince Spadea or Jonas Bjorkman of Sweden in the third round.

Despite committing 38 unforced errors, unseeded Henman played well against the world number one but was made to pay for each of his service lapses.

Federer broke Henman's serve in the second game of the match to grab a 3-0 lead held on to wrap up the first set.

In the second set, Federer grabbed a 5-2 advantage before Henman scored his only break of the match to trim the lead to 5-3. He could not capitalise, however, and Federer served out the set.

Henman, 31, improved his play in the final set but a loose service game allowed Federer to take a 6-5 lead before the Swiss served out the two-hour, two-minute match at love.

Joining Federer in the third round were Marco Chiudinelli and Stanislas Wawrinka, the first time Switzerland has had three men advance that far at the Open.