Karan Rastogi's doubles challenge at the Singapore ATP Challenger ended with a first round defeat even as his compatriot Purav Raja advanced to the quarter-finals.Rastogi and his Indonesian partner Christopher Rungkat, wild card entrants, lost tamely 1-6, 4-6 to second seed by Thai pair of Sanchai and Sonchat Ratiwatana.Another Indian in the doubles draw is Somdev Devvarman, who has teamed with South Africa's Rik de Voest. They will open their campaign against fourth seed Italians Flavio Cipolla and Simone Vagnozzi.Both Somdev and Rastogi have already advanced to the second round of the singles event.