Top seed Roger Federer successfully defended his NASDAQ-100 Open title by beating Ivan Ljubicic in straight sets in Sunday's final in Miami.

The Swiss star completed a hard-fought 7-6 (7-5) 7-6 (7-4) 7-6 (8-6) victory over the sixth seed from Croatia in a match dominated by serve.

Going into the match world number one Federer had won nine of his 12 previous meetings with Ljubicic, but the big Croatian more than held his own early on.

Both men were serving superbly from the outset, and it took a couple of sublime shots from Federer in the opening set breaker for him to finally get on top in the match.

Federer then went a break up in the second set, only to be pegged back straight away by Ljubicic, who produced plenty of forehand winners from the back of the court.

However when required the Swiss maestro raised his level in the second set tie-break, rallying from 4-2 down to take it 7-5.

Ljubicic then broke his man in the opening game of set three, but the writing looked on the wall when Federer broke back soon after.

The match then went into yet another breaker and Federer sealed the triumph with a fortunate net-cord on match point after saving a set point.

Federer has now won his last seven encounters with Ljubicic and extends his record this year to 27-1.