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 on Wednesday illustrated his almost fanatical 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 criticize 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 a high-caliber opener too but Nadal, as he has in winning 74 matches in a spectacular season of dominance, proved armor-plated in defense 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.
Nadal also finished 2008 and 2010 as world No.1 but this time his achievement is all the more impressive considering where he was in February.
After sitting out the second half of 2012 because of the knee injury that has dogged his career, Nadal missed the start of this season with a virus and even when he did eventually re-surface on south American claycourts he was still wincing in pain on occasions.
The outlook looked gloomy but nine months on he arrived in London with 10 titles from 16 tournaments, reaching the final of three more, and while he has gone to great lengths to insist rankings are no longer his goal, the way he celebrated when Wawrinka struck a forehand into the net after two hours 12 minutes spoke volumes.
"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 after reeling off his 2013 achievements which included five Masters 1000 Series titles, an eighth French Open crown and the U.S. Open.
"This is one of the best things that I did in my career, to come back to number one after three seasons. That's very difficult in our sport, and after a very important injury.
"Now I can really be focused only on the tournament because the year end is over."
Much has been made of Nadal's shift in emphasis to a more attacking style this year - a tweak that brought him unprecedented success on the U.S. hardcourts that used to furrow his brow.
Against, Wawrinka, however, it was his trademark defensive skills that proved decisive as he fought off Wawrinka's stylish onslaught.
Wawrinka hit twice as many winners as Nadal and won more points but when it mattered most, Nadal proved why he is one of the hardest men to put away.
When the Swiss broke Nadal's serve with an exquisite forehand winner to level the first set at 5-5 and then nosed 6-5 ahead the momentum had shifted his way.
At 5-5 in the tiebreak Wawrinka had his foe pinned against the ropes but somehow the Spaniard extricated himself with a desperate lob that forced a rash error from his opponent and when Wawrinka stumbled on the next point Nadal darted in to swat away a forehand.
Losing a 25th consecutive set to Nadal left Wawrinka staring up the equivalent of a sheer Swiss rock face but he launched a stirring fightback from 4-1 down in the second and came within a costly forehand error of taking it all the way.
All is not lost for Wawrinka who can still qualify for the semi-finals if he beats David Ferrer on Friday.
"It's all about me for the next one," Wawrinka, who beat Tomas Berdych on Monday, told reporters.
"I showed today that I'm playing my best tennis, that I can really, really fight."
(By Martyn Herman)