New Zealand's Michael Venus and American doubles partner Ryan Harrison have made a stunning start to the ATP Finals in London.

The 8th seeded team have beaten the defending champions, Finland's Henri Kontinen and Australian John Peers 6-4, 7- 6 (8-6) in their opening round robin match.

"It was a great match and we created a lot of opportunities returning serve. We didn't capitalise early on but we kept on playing well and got there in the end," Venus said.

Played in front of 17,000 spectators at London's O2 Arena, Venus and Harrison who are making their debut at the season ending championships were far from overawed.


"Walking out there it was very cool but we just enjoyed the whole moment and occasion and we just have to keep doing that throughout the tournament," Venus said.

They had three break points in Kontinen's opening service game but couldn't convert. However the chances kept coming and they broke serve in the 9th game on their sixth break point and Venus served out the set in 34 minutes.

The second set went with serve until the 11th game when the French open champions broke Kontinen for the second time in the match. But the Kiwi was broken for the only time of the match trying to close it out and the set went into a tie breaker.

Venus and Harrison had their first match point on the second seeds serve at 6-5 in the tie break and then saved a set point at 6-7, before Peers double faulted at 8-8 allowing Harrison to serve out the match 6-4, 7-6 in one hour and 29 minutes.

They earn $36,000US dollars for the victory on top of their $94,000 USD participation fee. Venus and Harrison play two more round robin matches this week against US open champions Jean-Julien Rojer and Horia Tecau who are seeded third and the 6th seeded French pair of Pierre Hugues Herbert and Nicolas Mahut. The top two teams from the group advance to Saturday's semi finals.

This was the third match of the year between the teams with Kontinen and Peers saving a match point in the fourth set of the Wimbledon quarter finals before winning in five sets. Venus and Harrison edged a tight match en route to the Cincinnati Masters semi -finals in August.

"It definitely helps playing some guys you have had success against before. I have also practiced with them a lot and that helps," Venus said.