The French Open champion had never won the title at the Rothenbaum, the only Masters Series on clay to have eluded the Spaniard. He lost to the Swiss world No1 in last year's final.

With the retractable roof open on centre court, Federer began the match strongly, opening up a 5-1 lead and twice serving for the set.

But Nadal refused to lie down and reeled off the next six games to take the first set and then broke Federer's serve in the first game of the second.

The Swiss broke back twice and missed a chance to level the match serving at 5-3 but upped his game in the tiebreak, winning it 7-3.

Nadal got the crucial break in the fourth game of the decider and closed out the match with a whipped crosscourt backhand winner after just under three hours of play.

The second-ranked Spaniard has 26 career titles, 21 of them on clay, including the last three French Opens. Nadal also won in Monte Carlo and Barcelona this year.

Federer lost his seventh match of the year and has only one title so far, at a relatively minor clay-court tournament in Estoril, Portugal.

What made Nadal's win even more impressive was that it came a day after an epic semi-final, which lasted more than three hours against Australian Open winner and world No 3 Novak Djokovic.

Nadal won 7-5, 2-6, 6-2 against a 21-year-old player he believes is on the way to being No 1 in the world.

'He has improved incredibly and is getting better,' the Spaniard said. 'He's going to be world No 1 within a few years, he's very good and very young.'

In contrast, Federer had a much easier time in his semi-final against Italian Andreas Seppi, winning 6-3, 6-1.

Meanwhile, Serbian fourth seed Jelena Jankovic cruised past French teenage qualifier Alize Cornet 6-2, 6-2 to retain her Italian Open title.

AGENCE FRANCE-PRESSE, ASSOCIATED PRESS