SAO PAULO -- Rafael Nadal is drawing inspiration from the Brazilian soccer great Ronaldo as he returns from an injury.

With Ronaldo watching, Nadal won the Brazil Open on Sunday for his first title after a seven-month layoff caused by treatment of his left knee. Nadal said Ronaldo is "an example" to be followed because of his determination to rebound from a series of career-threatening knee injuries.

Despite winning again, the Spaniard is still bothered by his knee and said he is far from fully recovered, although he hopes the victory will mark a new beginning in his career.

"Ronaldo is an example to a lot of people because of all that he was able to achieve despite what he had to go through with all the knee problems in his career," Nadal said. "He is definitely an example to me. He's an example of determination and hard work."

Ronaldo overcame three serious knee operations. The former Barcelona, Real Madrid, Inter Milan and AC Milan forward won two World Cups with Brazil and holds the tournament's career scoring record with 15 goals.

"He was unstoppable, one of the best players of all time despite all the bad luck he had with the knee," Nadal said.

The Spaniard was out of action since last year because a torn and inflamed tendon in his knee, an injury he says is improving.

"I didn't have so many problems, I never needed the surgeries," Nadal said. "But I can imagine how hard it must have been for Ronaldo with the complicated surgeries that he had to go through."

Nadal beat former world No. 3 David Nalbandian of Argentina 6-2, 6-3 to win his 51st title and first since beating Novak Djokovic last June for his seventh French Open championship.

The Brazil Open was Nadal's second tournament since his return. He played at the VTR Open in Chile the week before, losing the singles and doubles final. The final in Brazil was only his eighth singles match since the comeback.

Nadal looked far from his best in his first two tournaments and said that the knee injury still limited him physically.

"There are days that the knee still hurts and it's very complicated," he said. "I need some time to keep improving and become more competitive again. Let's see how it goes.

"The 11-time Grand Slam champion admitted the level of the competition in Brazil was not as high as in other tournaments.

Nadal will play another clay-court tournament in Mexico this month and hopes to be fully fit by the French Open. He hopes to play at Indian Wells, Calif., next month but hasn't made a decision.

"We are thinking day to day, week to week," the 26-year-old said. "We'll see how I feel before making a decision on where I'll be playing in the near future, it will depend on how the knee improves."