New York, Aug 14 - Indian tennis player Prakash Amritraj retired in the second set trailing 2-4 after losing the first 3-6 against Sergei Bubka Jr of Ukraine and conceded his pre-quarter-final match in the Leven Gouldin & Thomson ATP Challenger at Binghamton here.

Bubka, son of the legendary pole-vaulter Sergei Bubka, will meet Chilean Paul Candeville in the quarter-finals. Candeville beat Igor Sijslinc of the Netherlands 6-4, 6-4.

Prakash, however, put it across the Ukrainian in the doubles Thursday when he and his Pakistani partner Aisam-ul-Haq Qureshi beat Bubka and Russian Alexandre Kudrayavtsev 6-3, 7-6 (3) to enter the semi-finals.

Prakash and Qureshi next play South Africa's Rik de Voest and American Scott Lipsky who beat Israeli pair Amir Hadad and Harel Levy 6-3, 7-5.