Winning the men's singles at the 2011 Championships - a title which he calls "the most valuable event that you can think of in our sport" - was the clear highlight of a remarkable year for Novak Djokovic, a year which he hopes to round off by adding the Barclays ATP World Tour Finals title to an impressive collection, which includes three Grand Slams and five Masters 1000 crowns.
Four months on from that day in July when he defeated Rafael Nadal to land his first Wimbledon, Djokovic still cherishes the moment. "That was always the tournament that I dreamed of winning," he said and in the aftermath he was looking for something special with which to remember the peak moment of his tennis career. "I asked the groundsman if I could have a piece of the [Centre Court] grass," he smiled, "and although I could not get that, in return I got the net from the final."
That net, he confided, "I keep in a very special place at home." The Serb's dream moment came after two years of near misses in which he had gone out in the Wimbledon semi-finals and he paid full tribute to the team which helped him." We achieved what was unbelievable because we had been working very hard in the previous couple of years trying to get my game to the highest possible level, so obviously it was a success for everybody."
While he is in London Djokovic is toying with the idea of dropping in at Wimbledon, where he is an honorary member as a singles champion, to have a cup of tea and what he calls "to really experience Wimbledon when it is a little bit different from the tournament". First priority, however, is to become end-of-season champion at London's O2 Arena, a task which he will get under way on Monday evening with a round robin match in Group A against the big-hitting Czech Tomas Berdych.
He could not have landed a more demanding test of his fitness following recent worries about the state of his right shoulder, which has led to retirements and withdrawals. "Obviously I come to London with the highest expectations because of the year I have had," he said. "It is true that in the last couple of weeks I have been having some problems with my shoulder and four or five weeks ago I had an abdominal muscle injury, but I think I will be ready. I have been serving 100 per cent in the last two or three days, so for me the shoulder is fine and I can say I am recovered and ready to compete."
Djokovic's principal rival in the four-man Group A seemed certain to be Andy Murray, whose autumn run of three successive titles was halted by Berdych in the semi-finals of the Paris Masters event. But the Scot struggled his way to a 4-6, 5-7 loss against Spain's David Ferrer on Monday afternoon, exacerbating a groin injury along the way, which belied his earlier confidence in his ability.
Murray will decide on whether to continue in the competition after assessing the scale of his injury, but had earlier agreed that confidence has been the biggest factor in Djokovic's ascent to world No.1. "He showed that everyone is good enough if you can play your best tennis at the right moments. I don't think he has made huge, drastic changes to his game, it is just that bit of confidence." That said, Murray feels the Serb will struggle to repeat his unforgettable 2011 season."The margins are so small that a lot of things have to go your way."
Djokovic agreed that this year will be hard to follow up but promised he would try. "I can only be proud and positive. I know I have more expectation and more responsibility but I am ready for it. Everything I do in my life is a challenge and I am ready." He also offered Murray a boost of that magic ingredient - confidence - when he said, "Andy has already played a couple of Grand Slam finals and I am sure he will make it because he has the quality to do so. He has won against all the best players, he is a complete player who can play on all surfaces".
Meanwhile, in the opening matches of the season finale, Roger Federer was pushed in his quest to register back-to-back wins over Jo-Wilfried Tsonga. Having beaten the Frenchman in the Paris Masters final in Bercy last week, Federer had a rather tougher time against the burly Frenchman, coming through 6-2, 2-6, 6-4 in a topsy turvy match in front of the capacity crowd.
"He did well to serve bigger and better as the match went on," Federer said. "Once he got the upper hand in the second set, he started to swing more freely and got more dangerous. With me, it was just trying to stay calm, trying to wait for my chance, trying to create chances when he was not serving as well as he did at times. I was going to take those chances and hopefully come through with the victory, which it all came that way, exactly the way I hoped it to be."
The win was Federer's 60th of the 2011 season, the ninth consecutive year the Swiss has won 60 or more matches.
In the second singles encounter, Rafael Nadal and Mardy Fish contested a late-night thriller that kept O2 spectators in their seats well past 11pm. Nadal had lead from the beginning, taking the first set easily as Fish seemed hampered by nerves, but the American fought back in the second set to level the match. Momentum swung back and forth between the pair in the final set, Nadal seeing two match points come and go before finally prevailing, 6-2, 3-6, 7-6(3).
Meanwhile Max Mirnyi and Daniel Nestor defeated Rohan Bopanna and Aisam-Ul-Haq Qureshi 7-6(2), 4-6, 11-9 and Mariusz Fyrstenberg and Marcin Matkowski saw off Nenad Zimonjic and Michael Llodra 6-4, 5-7, 11-9 in the two doubles rubbers on Sunday.