Serbian third seed Novak Djokovic showed his desire to regain the ATP World Tour Finals crown as he started his campaign with a 6-3, 6-3 win over the Czech Republic's Tomas Berdych on Monday. Djokovic won this prestigious end-of-year event, featuring the world's top eight players, when it was staged in Shanghai in 2008, but he failed to get past the group stages after the tournament moved to London's O2 Arena last year. In this mood, the 23-year-old looks capable of taking back the title, won by Nikolay Davydenko last year, and he was far too strong for Wimbledon finalist Berdych in the first of his three Group A matches. Berdych admitted he suffered a case of stage-fright on his Tour Finals debut. 'If I would say no, then I would be lying. So, yes, I think you can see in the beginning that it affected my game a little bit,' he said. 'It's tough to come here after a couple of months when I didn't do that well. I'm struggling a little bit with confidence.' Djokovic added: 'Obviously when you have a first appearance in such a big occasion, it's not easy to handle the pressure and expectations and you could feel that in his game, especially at the start of the match. 'He made two double faults in the opening game. To start off with a break for me was very important. I think I did well. I couldn't ask for a better start to the tournament.' Sixth seed Berdych is the only player among the eight here not to have won an ATP title this season but he had no reason to feel inferior. The last time he played in London he defeated Roger Federer en route to this year's Wimbledon final. The 25-year-old also demolished Djokovic in the Wimbledon semi-finals before his fairytale run came to an end in the final against Rafael Nadal. However his form has dipped since then, while Djokovic has thrived following that Wimbledon disappointment, winning 26 of his last 32 matches and reaching the US Open final. The key to taming Berdych is to subdue the giant Czech's big-serve and Djokovic struck an early blow to his opponent's morale as he broke in the very first game. That was quite a statement of intent against such a powerful server and, suitably encouraged, Djokovic kept attacking Berdych with some relish. Although Djokovic wasn't able to convert two break points in the Czech's next service game, he was clearly the dominant force. He twice brought watching Argentine football legend Diego Maradona to his feet with superb shots, the first a perfect volley to finish off a long rally followed by a flicked winner on the run that left Berdych wrong-footed. Berdych was showing signs of crumbling under the strain of such a sustained assault and a pair of errors allowed Djokovic to break again and take the set. There was no let-up from Djokovic in the second set and he broke for a 2-0 lead when the increasingly flustered Berdych lashed a forehand wildly off-target. With Djokovic's serve working well, there was no way back for Berdych as the Serb easily closed out the match. World number one Nadal plays America's Andy Roddick in the other Group A clash later on Monday. 