Second seeds Mahesh Bhupathi [Images] and Mark Knowles [Images] squandered chances aplenty and went down 6-7 (4), 2-6 to Rik De Voest and Dmitry Tursonov in the quarter-finals of the US $2,233,500 Dubai [Images] Tennis championships.

With Mahesh's defeat, the Indian challenge ended at the event, as Leander Paes [Images] and Prakash Amritraj also exited with their respective partners.

The Indo-Bahamian partner squandered as many as eight break-points in a fiercely fought first set, which was eventually decided by a tie-breaker. The unseeded South African-Russian pair converted two of the three chances in the first set.

Bhupathi and Knwoles saved three break-points in the second set but were broken twice before going down in an hour and 17 minutes.

They will get 90 ranking points each and split US $14,050 prize-money between them.

Third seeds Paes and Lukas Dlouhy [Images] were sent packing in the first round, losing 4-6, 6-2, 8-10 to the unseeded pair of Simone Bolelli and Ivo Karlovic [Images].

The wild card pair of Amritraj and Aisam-ul Haq Qureshi of Pakistan also failed to make it to the second round, beaten by the Czech-Swede pair of Martin Damm [Images] and Robert Lindstedt 6-7 (4), 5-7.