Nadal return match ends with Ferrer retirement

Rafael Nadal of Spain serves to compatriot David Ferrer at the Rogers Cup tennis tournament in Montreal August 12, 2009.

MONTREAL (Reuters) - Rafael Nadal's first singles match after a lengthy injury lay-off ended abruptly on Wednesday when the Spaniard's Davis Cup team mate David Ferrer retired hurt during their second round encounter at the Montreal Masters.

With Nadal leading 4-3 in the opening set and having just broken his opponent for the second time, Ferrer calmly walked over to the chair umpire and said he could not continue after aggravating a left knee injury.

Ferrer had shown no signs of distress and in fact had dominated stretches of the match.

"I had problems with my knee, I cannot play," Ferrer told reporters. "I've had the problem since before Wimbledon and I want to take some treatment.

"I don't think (the injury is serious), I think next week I will play."

Sidelined for more than two months with tendonitis in both knees, Nadal was playing his first competitive singles match since his shock loss to Sweden's Robin Soderling in the fourth round of the French Open in May.

While Nadal moves on to a third round meeting with Philipp Petzschner of Germany, Wednesday's 37-minute workout answered few questions about the world number two's fitness.

"I need more days to have real test but it was ok," said Nadal, the defending champion.

"I tried everything 100 percent but when you come back from injury, it's difficult to move well the first match.

"Everything is positive, every match, every point, everything is helping me be ready as soon as possible when I return to my level ... I have another chance tomorrow to continue to improve."

(Editing by Ian Ransom)