Rafael Nadal in action against Roger Federer during the Hamburg Masters final on Sunday. Nadal won 7-5, 6-7, 6-3. (AP)

Hamburg: Spain’s Rafael Nadal struck a telling psychological blow a week before the French Open by beating world No. 1 Roger Federer in the final of the Hamburg Masters on Sunday.

The Spaniard claimed the only Masters Series event on clay to have eluded him by ousting the Swiss top seed 7-5, 6-7, 6-3 to give him the perfect preparation for the defence of his Roland Garros crown in Paris.

Federer, the defending champion who ended Nadal’s 81-match unbeaten run on clay in last year’s Hamburg final, 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 the Federer serve in the opening 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 deciding set and closed out the match with a whipped crosscourt backhand winner after just under three hours of play.

“Rafa has played incredibly well again the whole week and the whole clay season,” Federer told the 11,000 spectators after accepting his runners-up trophy.

“It’s hard for the rest of us but hopefully it will be a different story in Paris,” he added.

The Mallorcan, who now has a 10-6 winning record against Federer and 8-1 on clay, will be favourite to win his fourth title in Paris.

It may be the last time a Masters Series is played in the German port city.

The ATP wants to replace the Hamburg event with one in Madrid and the German Tennis Federation (DTB) has challenged the plan in a US court. A decision is expected in August.