Victory in two hours, 56 minutes for the Swiss world number one earned him an American tournament double for the second year in a row after back-to-back wins in Indian Wells and Miami.

"I'm extremely happy," Federer told reporters. "To win back-to-back like this is unbelievable. I never thought I'd do it again. It really feels great."

The Swiss, who has now won 28 of his last 30 finals, is unbeaten in Masters Series tournaments since he lost to Richard Gasquet in the Monte Carlo quarterfinals last April.

He has now beaten Ljubicic in their last seven ATP meetings and took his 2006 win-loss record to 28-1 -- a run that includes four titles.

Favourite Federer had to overcome more than 20 unforced errors in a 59-minute opening set that ended when he fired down a sixth ace in the tiebreak.

The Swiss went up a break for 4-3 in the second set but Ljubicic broke straight back but after two hours he had a two-set lead after another tiebreak.

Federer then recovered from a break down in the third set before closing out the match in another tiebreak to claim his 10th career title at a Masters Series event including the last four in a row including Hamburg, Cincinnati and Indian Wells.