A year that began with question marks hanging over his career will end with Rafael Nadal on top of the world and his win over Stanislas Wawrinka at the ATP World Tour Finals encapsulated why the Spaniard has a place in the pantheon of tennis greats.

He has certainly played better during a sensational season that begun in February after a seven-month injury layoff but the way he soaked up everything the inspired Swiss could muster to chisel out a 7-6(5) 7-6(6) victory yesterday illustrated his refusal to be beaten.

Wawrinka walked off the cavernous showcourt wondering how he is yet to take a set off Nadal in 12 meetings but it would be harsh judge to criticise the world number eight for failing to convert the fleeting chance that came and went in the second-set tiebreak.

He was within a whisker of taking the opener too but Nadal, as he has in winning 74 matches in a spectacular season of dominance, proved armour-plated in defence and ruthless when given a chance to attack.

Nadal arrived in London for the glitzy season-ender needing two wins to fend off Novak Djokovic in the race to end a year as world No.1 for the third time in his career.

After dismantling compatriot David Ferrer on Tuesday, he was stretched to the limit by Wawrinka in his second Group A match.

By winning in straight sets he also assured himself of a place in the semi-finals and few would bet against the 13-times grand slam champion going on to claim the only title missing from his CV.

“Today was more important to secure the number one (ranking),” Nadal told reporters.

“I think after all what happened last year, I felt I deserved to be there at the end of the season. And today I did,” Nadal added.

Other result: Berdych bt Ferrer 6-4 6-4.