Rafael Nadal has claimed that Novak Djokovic's achievements throughout 2011 will be "probably impossible to repeat".
The Spaniard slipped to a four-set defeat at the hands of the world number one during the final of the US Open yesterday, taking Djokovic's tally of Grand Slams for the season to three.
Djokovic has won 64 of his 66 matches this season and has also emerged victorious from his last six successive meetings with Nadal.
Former world's best Nadal believes that such statistics will be difficult to replicate.
"Obviously I'm disappointed but this guy is doing unbelievable things so congratulations Novak and your team for everything," Nadal said on court after the match.
"What you did this year is probably impossible to repeat.
"I try my best in every moment. These kind of matches are very difficult, it brings your body to the limit."
Nadal claimed the other Grand Slam available this year, defeating Roger Federer in the final of the French Open.
