London, Nov 17 (IANS): Danii Medvedev defeated Alexander Zverev in straight sets during an ATP Finals match at London's O2 Arena on Tuesday.

Russia's Medvedev won 6-3, 6-4 against his German opponent to join Novak Djokovic on top of the Group Tokyo 1970.

Zverev hit four double faults in his first two service games, and never found rhythm with his second serve going. Medvedev won 79 per cent of his second-serve return points (15/19) on way to his one-hour, 29-minute victory.

Medvedev is high on confidence having beaten Zverev in the Rolex Paris Masters Final a few days back.

"Confidence is the key, for sure. Winning an [ATP] Masters [1000] always helps the confidence," Medvedev said.

"I knew that I can play good. It was a little bit shaky from both of us in the beginning from one [point] of view, but from the other [point] of view, I think there were some unbelievable points. To be honest, the intensity of the match was one of the most [intense] I had in my career."

Medvedev is the first Russian to compete at the ATP Finals in consecutive seasons since Nikolay Davydenko made five straight appearances from 2005 to 2009.