LONDON - Local hero Andy Murray and world No 1 Novak Djokovic of Serbia both claimed victories at their opening matches in Group A at the ATP World Tour Finals on Monday.

Britain's Andy Murray serves to Tomas Berdych of Czech Republic during their men's singles tennis match at the ATP World Tour Finals in the O2 Arena in London, Nov 5, 2012. [Photo/Agencies]

Third seed Murray fought back from one set down to defeat fifth-seeded Czech Tomas Berdych 3-6, 6-3, 6-4 in two hours and 17 mintues, making their win-loss record 4-4 in their eight meetings.

Djokovic began his campaign with a 7-6 (7-4) 6-3 victory over Jo-Wilfried Tsonga.

The top seed, who had last the previous four meetings between the pair on indoor courts, proved too strong for the Frenchman, triumphing in one hour and 39 minutes.

Serbia's Novak Djokovic slides during his singles tennis match against France's Jo-Wilfried Tsonga at the ATP World Tour Finals in the O2 Arena in London, Nov 5, 2012. [Photo/Agencies]

Crucially the Serbian took two of the three break point chances he created in a tight tussle, though all of them came in a second set that he dominated.

While Djokovic has secured his top position this year, Murray, who is making his fifth straight appearance at the ATP World Tour Finals, will finish year-end No 3 in the world rankings.

"The noise and the atmosphere at the beginning of the match was great," said Murray. "I thought I started the match well. I just didn't quite take my chances early on. Both of us I thought served pretty well and weren't losing too many points on our first serve. It can hinge on a couple points here or there. Getting the break for a 3-1 lead gave me the advantage in the second set. But the third set was tight as well."

Tomas Berdych of Czech Republic serves to Andy Murray of Britain during their men's singles tennis match at the ATP World Tour Finals in the O2 Arena in London, Nov 5, 2012. [Photo/Agencies]

Berdych admitted, "I think it was a very, very good and solid match, from both of us. Unfortunately, small details just decided it today. I think the biggest moment was in the second set, 1-1, when I had three break points."

The 25-year-old Murray is bidding for a fourth title of the year, which includes the London 2012 Olympics gold medal, US Open and Brisbane International. He has lost in the 2008 and 2010 semifinals at the ATP World Tour Finals.