David Ferrer retired against Rafael Nadal while serving up 4-3 in the second set with a break. Earlier, the world no. 1 had won the first set 6-3. In press conference, Nadal shared his sadness for his friend's leg injury. 'I'm very sad about what happened to him in his last match probably on a Grand Slam.

But that's like this. That's life. He deserved a better finish on a Grand Slam,' Nadal said. 'But I am sure that he will have the right finish for him in the tournaments that he decides to play to finish his career.

I am very, very sorry for him. He is one of my closest friends on tour. We've shared amazing moments together, Grand Slam finals, Davis Cup wins... and he's one of the greatest players our country has ever had. 'David never won a Grand Slam, maybe because of bad luck and because he had to play in the same era as three players who won all the titles.

There are players who won a Major despite being worse players than him. 'In the second set I had seen that he wasn't doing well and I lost focus,' added Nadal. 'There was an unbelievable humidity and I struggled a lot.

I hope in the next days it will be better.' Ferrer said: 'It was special because I finished my last Grand Slam playing in the centre court with Rafael Nadal, because he's a very good friend. [I'm] sad because I couldn't finish the match.

[But] it's not a problem. I am a lucky man.' ALSO READ: David Ferrer: 'It will be my last US Open. Facing Rafael Nadal is a gift'