Now we are three

His stamina has been called into question, he falls ill more frequently than most players, he needs to improve his all-court game and his armoury lacks a killer weapon. One quality nobody would suggest Novak Djokovic lacks, however, is confidence.

"I've always believed I can achieve anything," the 21-year-old Serb said. "I've tried to be realistic, but at the same time I've always set myself the highest possible goals. I always thought I had enough quality to reach my highest targets, even when I was a junior. That's continued through to my professional career.

"There are so many players coming through, but I felt I was always a step ahead of them. I made my breakthroughs faster than them, though I always tried not to think about what they were doing. I set my own goals and tried to focus on them. I always aimed for the top and I was always comparing myself to the best players in the world – and I think that's why I'm here."

At his current rate of progress this son of the mountains – his father, aunt and uncle were all professional skiers – could conquer even the game's highest peak this summer. From base camp last January, when he was No 16 in the world rankings (Andy Murray, who is one week older, was No 17 at that time), Djokovic climbed to No 3 after Wimbledon and has been closing on the summit ever since. Victory here in Paris would see him overtake Rafael Nadal, world No 2 for the last three years, while even Roger Federer, No 1 since February 2004, is within his sights, particularly given the Wimbledon champion's recent poor health and patchy form.

The Federer-Nadal duopoly went almost unchallenged for two years, but Djokovic's emergence has changed men's tennis into a three-way fight for supremacy. Federer, who is in the opposite half of the draw to his two rivals here, is 1,090 ranking points ahead of Nadal and a further 360 clear of Djokovic – the rolling list is based on performances over the last 12 months with, for example, 1,000 points awarded for a Grand Slam title – but there is then a gap of another 1,935 to the world No 4, Nikolay Davydenko.

The domination of the big three is such that Bercy 2006 was the last Masters Series or Grand Slam final which did not feature one of them. Between them they have won 18 of the 21 subsequent events (including the last two Tennis Masters Cups), Federer claiming seven titles, Nadal six and Djokovic five.

An even more up-to-date picture is "The Race", the ATP list that awards points for the calendar year and decides which eight players appear in the season-ending Tennis Masters Cup. Djokovic (521 points), having won the Australian Open and added two Masters Series titles, is just ahead of Nadal (510) and significantly clear of Federer (360).

The Serb's continuing progress followed a minor hiccup at the end of 2007, which he finished with five successive straight-sets losses, including three in the Tennis Masters Cup in China. "I didn't want to dwell too much on the defeats I had then because I didn't want them to ruin the best season of my career," he said.

"I know I was expected to do well in Shanghai, considering I'd been playing so well indoors and on hard courts, but these things happen. You always have ups and downs, especially when you're young. At the end of the season I sat down and thought about all the things that I could do to improve, but the most important thing for me was to have two or three weeks of complete rest. I didn't do a thing at the end of the year. That's why I came fresh into the new season."

Djokovic has retired in three matches in the last 12 months, including last year's Wimbledon semi-final against Nadal, has had surgery for breathing difficulties and admits he is prone to sickness.

"I'm a little, sensitive, tiny guy," he smiled. "Unfortunately every time I come back from a long trip and experience a change of climate my body reacts. Everybody's different. Some people are more sensitive and I get sick pretty often, so I'm surprised when I'm healthy. No, I'm joking. I just have to be very careful about everything I do in between tournaments because I really want to be 100 per cent ready for every tournament I play."

Most of Djokovic's successes have been on hard courts, but he grew up playing on slower surfaces (nearly all the courts in Serbia are clay), reached the semi-finals here last year and has enjoyed an excellent clay-court season. Entering just three events, he won his first Masters Series title on clay in Rome and lost in the semi-finals in Monte Carlo (where he retired with tonsillitis against Federer) and in Hamburg (where he lost in three sets to Nadal).

If there are no outstanding features to his game, there are also no weaknesses. "He's very good at everything," Murray said recently. "He moves exceptionally well. I don't know if there's one particular shot that is better than anybody else's, but as a whole game his is up there with the best. He doesn't hit the ball hard. He changes direction of the ball very well and hits good angles off both wings. He can take the ball up the line very well, which is tough to anticipate, and has a good drop shot."

Djokovic believes his clay-court game has improved significantly and that he will be mentally tougher than on previous visits here. "I'm coming to the French Open as a Grand Slam champion and world No 3," he said. "I've won a couple of major events in the Masters Series, so I have enough confidence and experience to cope. I'm a more mature player and I believe much more in myself. I believe that I can win against Rafa on clay and against Roger or any other top player on any surface."

While Djokovic's confidence can seem to border on arrogance, his sense of humour and evident enjoyment of his fame and fortune have brought a welcome element of fun into what can be a straight-faced sport. We may have seen the last of his player impersonations – he stopped when he heard that some of his subjects felt offended – but his karaoke version of "I Will Survive" remains a YouTube classic. He was the life and soul of a players' party in Dubai, parading proudly in local robes and headgear, delighted the crowd in Rome with his mock-amorous embrace of Gabriela Sabatini and appeared on The Tonight Show with Jay Leno in the United States.

Rarely reluctant to offer an opinion, he was outspoken earlier this year in his opposition to Kosovan independence. "Kosovo is part of Serbia and I'm going to always think in that direction because it's the heart of the country," he said. "You can't take away something that is our history, our cradle, that is everything we have in our religion and the history of the Serbian people."

Djokovic is most at ease surrounded by his friends and family, who are a regular fixture at his matches. In Melbourne this year he particularly enjoyed returning every night to a rented apartment with his parents and two younger brothers, both of whom are promising players.

"When you travel around the world as a tennis player you spend most of your time in hotels, so it's good to be with your family," he said. "It was a nice change to go back to the apartment and have a meal with my family. My mother does most of the cooking. There are a lot of Serbian specialities that I like and we love it when she makes pancakes. We have a pancake restaurant back home and she makes them better than anyone."