Rafael Nadal of Spain serves during his men's singles tennis match against Stanislas Wawrinka of Switzerland at the ATP World Tour Finals at the O2 Arena in London Nov 6, 2013. [Photo/Xinhua]

LONDON - Rafael Nadal of Spain sealed the year-end No 1 ranking for the third time by edging Stanislas Wawrinka 7-6 (5), 7-6 (6) at the ATP finals here on Wednesday.

Nadal also qualified for the semifinals of the event with two straight wins in Group A. He crushed fellow Spaniard David Ferrer 24 hours ago.

The 13-time Grand Slam winner can't be surpassed by No 2 Novak Djokovic of Serbia in the world rankings with two victories.

Nadal, who won 10 titles this season, also ended the season as world No 1 in 2008 and 2010.

"A lot of emotions today, it's the perfect scenario to finally be the year-end number one," Nadal said.

"Being number one at end of the season is something really difficult as there are some unbelievable competitors out there."