It is rather fitting that the two best players in the world will compete in the last match of 2013 for the right to become this year's ATP World Tour Finals champion.
Rafael Nadal has been the player of the year after his explosive return to the tour in February - winning two grand slams, five Masters 1000 crowns and three other titles after being out with a career-ending knee injury for more than seven months.
Novak Djokovic is determined to show that he is still the king, and since losing in the final of the US Open has played the best tennis of his season. The Serb is currently on a 21-match winning streak, and will be desperate to defend his trophy at the O2 and stop Nadal from capping off his phenomenal year with a maiden tournament win.
Nadal will end the year as the world No. 1, which was a position held by Djokovic for the past two seasons and right up until October. Rafa was his opponent in the US Open final, and it was only a matter of time before Nadal would leapfrog Djokovic in the rankings.
But Djokovic is not frustrated at not being the top-ranked player for 2013. What will mean more to him is to successfully defend his crown, becoming the eighth player to do so, and to win a fourth trophy in as many events to add to his wins in Beijing, Shanghai and Paris.
"We both want to crown this season in the best possible way and end it with the title. It doesn't matter where we play each other, there is a lot on the line," Djokovic said after his victory over Stanislas Wawrinka - his first match of this year's event where he has not been required to go into a final set.
And when he was told that Nadal labelled him the favourite, he added: "It's everyone's choice to pick who the favourite is. Of course I'm not going to say I'm the favourite because we are trying to switch the roles of the favourites wherever we go. This is probably the best possible final we have here in London."
Much has been made about Nadal not having the World Tour Finals listed on his roll of honour, and so has the fact he has downplayed his chances of winning the event this week in London.
But after he chalked up another victory over his great rival Roger Federer in the semi-finals, the Spaniard's dream is just one match away from being fulfilled.
"For me, every match means a lot, and so does every tournament. It's true that this tournament is special and I've never had the chance to win here," Nadal expressed after contemplating what being crowned World Tour Finals champion would mean to him.
"It will be a great year if I have the chance to finish with a victory, but there is a lot of hard work remaining, and it's probably the most difficult [match]. If I don't play my best, I won't have any chances."
Nadal has been close to his best on a surface and surroundings he least favours, but at the beginning of the week when he joked that he prefers outdoors because "he likes the sunshine", the Spaniard has lit up the O2 over the past week with displays that audiences were cruelly deprived of 12 months ago when he was absent from the circuit.
"I was able to play a little bit better and better every day during the tournament, so we'll see in the final if I have the chance to play better than what I did," he added.
The pair have met on 38 previous occasions with Nadal leading 22-16, and they have already clocked up the most meetings in the Open Era, so to say they know each other inside out by now would be something of an understatement.
"It all ends here" is the tournament slogan, and Nadal and Djokovic will bring the curtain down on what has been a fiercely competitive campaign.
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