India's Mahesh Bhupathi and his doubles partner Mark Knowles were in confident mood heading into the ATP World Tour Finals last four, despite losing their concluding group match.

Bhupathi and his Bahamian partner, the third seeds, lost 6-4, 7-6 (11/9) to top seeds Daniel Nestor of Canada and Nenad Zimonjic of Serbia at London's O2 Arena in their Group A clash.

Bhupathi and Knowles had already qualified for Saturday's semi-finals of the season-ending tournament, having won their first two games, but were undeterred by the defeat and ready to face whichever partnership they are drawn against from the unresolved Group B.

"Any of the three teams that come through, we've played them multiple times this year. We're playing well, which is the most important thing," Bhupathi said.

"We have to look after ourselves and our games. If we execute like we have been the last three matches, I think we'll have a good shot to win on Saturday."