India’s Prakash Amritraj advanced to the second round of the $380,000 Mercedes-Benz Cup tennis tournament in Los Angeles after sixth seed Marat Safin retired with a wrist injury.Amritraj, a wild card, was leading 5-3 in the first set yesterday when the Russian retired with an injury to his left wrist.Amritraj will now take on Kenneth Carlsen of Denmark in the prequarterfinals, according to information received here.Former world No. 1 Australian Lleyton Hewitt, now ranked five, is the top seed in this hard court tournament.In doubles, Prakash and his cousin Stephen Amritraj will take on top seeds Rick Leach and Brian MacPhie of USA in the first round. Meanwhile, the Indo-Pak pair of Rohan Bopanna and Aisam-ul-Haq advanced to the doubles quarterfinals in the Colorado Classic Challenger tournament in Denver, USA.The top seeds beat American wild card pair of Mark Dietrich and Ogidi Obi 6-4, 6-3.