No need for extra Federer motivation against Nadal

INDIAN WELLS, California (Reuters) - Refreshed after taking a break to resolve a lingering back injury, Roger Federer is eager to resume his rivalry with Rafael Nadal at the Indian Wells ATP tournament starting Thursday.

Federer, sidelined since losing last month's Australian Open final to the Spaniard, said he was more motivated than ever to end a losing streak of five matches against Nadal.

The Swiss world number two, a three-times champion at the Indian Wells Tennis Garden, is seeded to meet top-ranked Nadal in the tournament final.

"I love playing matches against him, especially those five-setters, seeing if I can hang with him physically without a problem," Federer told reporters Wednesday. "He's the greatest challenger I've ever had."

"I am really motivated because I don't know how much better he can play. I don't know how much better I can play but I am right there and he's playing the tennis of his life."

Federer was unable to seal a record-equaling 14th grand slam singles title after losing to Nadal in a five-set thriller at Melbourne Park, but he was largely pleased with his performance.

"I thought I played a great match for four-and-a-half sets," the 27-year-old said. "I guess I let go a little bit at the end. He looked tired and I couldn't take advantage of it.

"I think I played great off the baseline, I just didn't serve great and I think that cost me the match also.

"He's a great player at the moment," Federer said of the Spanish left-hander, whose last three victories against the Swiss have come in grand slam finals.

"He has proved himself on all surfaces now and I guess it all started for him when he beat me comfortably at the (2008) French Open. He forgot how it feels losing and I had lost to him a couple of times before that."

Federer said he would continue working with Swiss Davis Cup captain Severin Luthi as his part-time coach after an experiment last month with Australian Darren Cahill had been abandoned.

"I am very happy with Severin," he added. "We have been working the last one-and-a-half years together, so nothing really changes. I just continue with the great team that I have."

(Editing by Peter Rutherford)