London, Nov 6 (EFE).- Spain's Rafael Nadal edged Stanislas Wawrinka 7-6 (7-5), 7-6 (8-6) Wednesday to clinch the year-end No. 1 ranking and advance to the semifinals of the Barclays ATP World Tour Finals for the fourth time.
Nadal, who routed countryman David Ferrer on Tuesday, needed to win two matches at this year-end event to assure himself of the top ranking for 2013.
In an on-court interview inside London's O2 Arena, the Spaniard said he was thrilled to lock up the year-end No. 1 ranking at a "fantastic stadium and before this crowd."
The 27-year-old also finished the year No. 1 in 2008 and 2010, but this year was particularly special because he was out of action for much of last year with a serious knee injury.
Nadal said in the post-match press conference that getting back to No. 1 wasn't his "main goal," but that he felt he "deserved to be there" after coming back from injury and having so much success this season.
Nadal started his comeback in February at three small clay-court events in South America and enjoyed immediate success, reaching the final of nine straight tournaments - and winning seven of them - before suffering an early exit at Wimbledon.
Despite that disappointment, Nadal added to his record haul at the French Open by capturing his eighth title and capped off an undefeated run in the North American hard-court season by winning his second U.S. Open.
He now has a chance to capture his 11th title of the season and win his first-ever ATP World Tour Finals, an indoor hard-court event that is the biggest title to elude Nadal in his career.
The Spaniard recovered the No. 1 ranking on Oct. 7 and held off a stiff challenge from Serbia's Novak Djokovic, who has won 18 straight matches since losing to Nadal in the U.S. Open final.
Against Wawrinka on Wednesday, the world No. 1 started strong and went up an early break by committing precious few unforced errors.
But the Swiss got the break back in the 10th game and the first set came down to a tiebreaker, which the Spaniard won when Wawrinka stumbled at the net on set point.
The second set was nearly a carbon copy of the first, with Nadal seizing a break-of-serve lead before Wawrinka battled back and forced another tiebreaker.
Nadal saved a set point when serving at 5-6 and then sealed the victory thanks to two unforced errors from Wawrinka.