Rafael Nadal has claimed that it was "important" for him to finish the season positively following a "tough year".

The Spaniard, who has 14 Grand Slam titles under his belt, has had an inconsistent campaign due to injuries and fitness concerns.

However, the 29-year-old has been in scintillating form at the ATP World Tour Finals in London as he has finished the round-robin stage of the tournament unbeaten.

Nadal claimed his third consecutive win against the top seven in the world in a three-set triumph over David Ferrer this afternoon.

"It was very important for me to finish the season playing like this, playing against the best in the world," Nadal said after the game.

"It's been a tough year for me. Some strange feelingas for me on court at times, but I always work hard and in the last five weeks I'm playing much better."

Nadal will take on world number one Novak Djokovic in the semi-finals on Saturday at the O2 Arena.