Indians failed to impress on day one of the ONGC [Get Quote] ATP Challenger tournament as all four of them in singles action lost in New Delhi on Monday.

Tushar Liberhan lost to Sebastien De Chaunac of France [Images] 6-2 4-6 6-1. Liberhan managed to win the second set but was unable to maintain the momentum and was thrashed in the decider.

Russia's [Images] Pavel Chekhov defeated Prajnesh Gunneswaran 7-6(3) 6-4 and Indian Navdeep Singh was knocked out by An Jae Sung of South Korea in straight sets 6-3 6-3.

Cecil Mamit of the Philippines got the better of Sunil Kumar Sipeaya whom he sent packing in a close fought encounter 4-6 6-3 7-6(4).

Indians could not find any form in doubles either as Karan Rastogi [Images], partnering Austrian Martin Slanar, went down 6-1 7-5 to Chinese Yu Yuan Xin and Shoo Xuan Zeng. However, the experienced Indian trio of Rastogi, Harsh Mankad and Rohan Bopanna are yet to take to the court in singles.

Meanwhile, top seed Ivo Minar of Czech Republic defeated Couillard Guillaurne 6-4 6-4 while unseeded Dieter Kindlmann (Germany [Images]) benefitted when third seed Kristian Pless of Denmark retired hurt before the third set.

Kindlmann won the opening set 7-5 while Pless came back to win the second in a tie-breaker 13-11.