LONDON (Reuters) - Carlos Moya knew Rafael Nadal was good when he first set eyes on his fellow Mallorcan as an 11-year-old but he never imagined the precocious young talent would become a serial winner of grand slam trophies.
Speaking after bidding an emotional farewell to tennis on Sunday when Nadal hosted an on-court ceremony for his close friend at the ATP World Tour Finals, Moya said the world number one was now on the way to even surpassing the milestones achieved by 16-times grand slam winner Roger Federer.
"He's been amazing player. He is amazing player," the 34-year-old Moya, who was embraced on the O2 Arena's Center Court by past and present players including Federer, Novak Djokovic and Andy Murray, told reporters.
"You know, knowing him for so long makes it special for me because first time I met him, he was just 11, 12 years old.
"So he was a good prospect of being a good player but you never know what can happen. I realized he had something special, but could never think that he could be that good, to be honest.
"He's one of the greatest ever. But he's on his way to become, who knows, maybe the greatest."
Moya, the former French Open champion and the first Spaniard to top the ATP rankings in 1999, announced his retirement this week because of a long-term foot injury.
Nadal describes Moya as his mentor and the 24-year-old, who plays Roddick Monday, was clearly emotional as he spoke of Moya's contribution to the sport.
"It's a sad day for me because I'm saying goodbye to a friend and tennis is saying goodbye to a great ambassador," the nine-times grand slam winner said in front of thousands of fans who had just watched Murray's victory over Robin Soderling.
"He was the first Spaniard to be number one and he helped me a lot when I was a young player. I've missed him a lot this last year when he's not been on the circuit."
Moya said watching Nadal emerge had helped his own career in which he won 20 titles, including Roland Garros in 1998.
"Maybe I said a thousand times, but the same way I helped him, I think he helped me," Moya said. "When he was 13 or 14 we were practicing together. I was near the top 10 and sometimes he was beating me during the practice.
"That made me think, that made me improve and evolve. You see a kid like this kicking your ass so you try to avoid that. So he made me improve and made me more positive.
"I cannot say that Rafa owes me anything at all. He deserves all what he's winning. Of course, aside from how good he is, he's a great person."
(Editing by Pritha Sarkar)