To be honest, I haven't felt at my best since this tournament began. I didn't feel good with the court or the balls. But those are excuses. You have to accept when you don't play well and somebody else does.
When asked by a reporter why he spent so much time well behind the baseline against Fernando Verdasco in the Australian Open semifinals 2009 
In your career you have a lot of good moments and bad ones. The important thing is to have enough motivation to keep working all the days with humility and trying to be a better player than before. I am going to try to continue doing this." 
Everybody likes to say that Roger Federer is the Greatest Player of all time because its so nice to watch him play...but you have got to throw in Nadal's Mind as well...and That's the GREATEST OF ALL TIME!!!
Mats Wilander in a video about Nadal's comeback in the year 2010 in which he won three consecutive grand slams.
"He has never broken a racket in anger. It would be showing a lack of respect to people who actually have to buy the equipment to play the sport."
"He is like a beast, an animal, on the court. He's very strong and he's very well prepared."
Guillermo Coria after losing to Rafael Nadal in Monte Carlo. 
"Almagro … is a guy that's won like 11, 12, clay court titles, won them all on clay. The guy's very, very good clay-court player.I don't think he's ever played better than he played - and he still can't win a set. Like how discouraging it is to play Nadal on this surface.Ah, God, I have seen him a thousand times. I just watch this guy and it's hard to even know where to begin to pick one thing.The way he's improved his game, like his serve, the parts of his game where he can move forward, his volley, the defensive ability he's got to track down balls and just make you play extra shots.And the way he sort of slides into balls and puts away a shot - shots that seem like impossible when I was playing - it was unheard of."
John McEnroe talking about Rafa before the 2012 Roland Garros Men's singles final between Novak Djokovic and Rafael Nadal