Melbourne, Jan 27 (DPA) Rafael Nadal's dream of four straight Grand Slam titles ended Wednesday, with the world number one shattered by a 2-6, 3-6 quarter-final loss to fellow Spaniard David Ferrer at the Australian Open.

Nadal suffered from what appeared to be a hamstring injury, but the top seed refused to confirm any diagnosis.

"It was a difficult day for me, I tried my best, I could not do more," he said.

"Tonight I think I played against a great player, a great opponent. Today I really can't do more than what I did. So, he played at a very high level, and I was not able to compete against him tonight."

Nadal appeared close to tears in the closing stages of the loss after seeming to pick up the injury in the long, 17-minute second game of the match against his seventh-seeded opponent.

"It is obvious that I did not feel at my best. I had a problem during the match, at the very beginning. After that, the match was almost over."

"For me, it is difficult to come here and speak. In Doha (early January) I was not healthy (virus). Today I have another problem. Seems like I always have problems when I lose, and I do not want to have this image."

"I prefer not to talk about that today."

Nadal's loss sends Ferrer into the semi-final against 2010 finalist Andy Murray.

"This is one of my bad moments," said Nadal. "One of the negative moments. That is part of the sport. I am a very lucky sportsman in my career.

"I have to accept the fantastic moments that I had during a lot of years with the same calm as when I have problems. And if I am ready to accept both things, I am going to be able to come back and play my best tennis another time."