As a vintage season in which the big four of men's tennis have shared the major prizes enters its final weeks, Novak Djokovic is chasing an honour that would set him apart - year-end number one. The Serbian world number two saved five match points on Sunday to overcome fierce rival Andy Murray and win the Shanghai Masters, a huge step towards finishing in top spot for the second year in a row. Djokovic, who enjoyed one of the finest seasons in tennis history last year, ceded his number one ranking to Roger Federer after the Swiss won Wimbledon. Now he wants it back. "It's my biggest objective in this moment. It's something I'm aiming for," said Djokovic, 25, when asked what it would mean to finish at the top for two years in a row. "Obviously this [Shanghai win] is going to be a huge confidence boost and is going to help me in the race for number one." But he warned: "It's still not done. I still have to play well indoors." It would take an unlikely sequence of events for the Serbian to fail in his quest, as he has fewer points to defend in the closing weeks than Federer in the rolling 12-month rankings. Speaking in the afterglow of his thrilling come-from-behind victory over British third seed Murray, Djokovic, who won the Australian Open at the start of the year, said he had had an "unbelievable season". "Comparing to 2011, results-wise maybe it wasn't at the top, because I had three grand slam titles. This year I have only one. But I've had an incredible year," he said. "We have to pay a little bit of respect to the other players. They've had an amazing year also. At this level, you cannot expect to win all the matches." A surprisingly sanguine Murray, 25, said he had endured tougher losses despite the agony of the chances that slipped away. Speaking about Djokovic, he said: "He's been at the top of the game now, likely to finish number one, that will be two years in a row. Of course, the number one player in the world is what you want to get to." Federer, 31, started his 300th week at number one yesterday.