NOVAK Djokovic fought back from a set down to defeat Juan Martin Del Potro and reach the final of the Barclays ATP World Tour Finals.
The world No 1 had looked in trouble when he went a break down in the second but Del Potro won only three of the last 14 games as Djokovic triumphed 4-6, 6-3, 6-2.
It is the first time the 2008 champion has reached the final since the tournament moved to the O2 Arena three years ago, and he will meet Roger Federer this evening.
Djokovic was the only unbeaten player in the group stages and had had a day’s rest, and he looked every inch the best player in the world in the early stages. Del Potro was having to find some special shots just to stay on level terms, notably a forehand creamed down the line to save a break point in the second game.
The sheer power of 6ft 6in Del Potro was pushing Djokovic to overhit and, although he saved a break point in the seventh game, he faced two more a couple of games later and this time Del Potro struck.
The 24-year-old then served out the set to love, and he kept the momentum going at the start of the second set.
Djokovic saved three break points in the opening game but he was under pressure all the time and he had no answer to another monstrous forehand from Del Potro in the third game. It seemed to be getting away from Djokovic but he roused himself, taking his fourth chance to hit back immediately when Del Potro for once missed a forehand down the line.
And the Argentine won only one more game in the set as Djokovic levelled up, breaking for the second time at 4-3.
The effort of the first set seemed to have taken a lot out of Del Potro and he looked weary as he was broken once more in the third game of the decider. In contrast, Djokovic had a spring in his step again and the end was a swift in coming, the top seed clinching it in two hours and 12 minutes.