British player Jonny Marray and doubles partner Frederik Nielsen saved two match points before coming through to win their opening match at the ATP World Tour Finals.
The Wimbledon champions were taken to a match tie-break by Mahesh Bhupati and Rohan Bopanna but eventually came through to claim a 6-4 6-7 (1-7) 12-10 win.
Marray and Nielsen, who are the lowest seeds in the tournament, made a good start and took the first set after securing the match's only break of serve.
They then earned a match point in the 12th game of the second set but passed up the opportunity as Marray netted a return.
And the Indian pair made their opponents pay by dominating the tie-break to take the contest into a deciding breaker.
Bhupati and Bopanna went 5-1 up but Marray and Nielsen fought back to level matters before fending off the two match points, the second of which they snuffed out in spectacular style.
A double fault then brought up a match point for Marray and Nielsen and the latter completed the win with a powerful serve.