After Nadal beat Federer in a fifth-set tiebreaker last year, both players pulled out of the following week's Hamburg Masters citing fatigue. For this season, the ATP tour introduced best-of-three set finals for the Masters Series.

"It was great for Rome, but not fair to Hamburg," Federer said. "I like battling for five sets, but it's too tough on your body. Now all the tournaments will have the chance to see the best players."

The ATP said the Rome final spurred the change.

"The players' health is really important for us and we're trying to do everything possible to protect them," said tour spokesman Nicola Arzani.

Federer and Nadal have byes for the first round of this year's Rome tournament, which begins Monday.

Federer will face either Nicolas Almagro or Tim Henman in the second round, while Nadal will go up against either Robby Ginepri or Daniele Bracciali.

Federer arrived in Rome last weekend and has been practicing on the clay courts all week with coach Tony Roche. He made a brief trip to Mallorca for Wednesday's exhibition loss to Nadal on a half-grass, half-clay court.

The Rome tournament is an important clay-court tuneup for the French Open, which begins May 27, and Roland Garros is the only major that Federer has not won. He lost to Nadal in last year's final in Paris.

"I don't necessarily want to become No. 1 on clay as much as I want to win Roland Garros," Federer said. "That's my goal."

Nadal holds a 72-match winning streak on clay that stretches back to April 2005. He has won the Rome title the past two years, and both finals were memorable. In 2005, he shook off a blood blister to beat Guillermo Coria in the longest final in the Open Era _ 5 hours, 14 minutes.