India's Prakash Amritraj advanced to the second round of the $380,000 Mercedes-Benz Cup in Los Angeles, USA, after sixth seed Marat Safin retired after suffering a wrist injury.

Amritraj, a wild card, was leading 5-3 in the first set on Tuesday when the Russian retired with an injury to his left wrist.

Amritraj will now take on Kenneth Carlsen of Denmark in the pre-quarterfinals on Wednesday.

Former World No. 1 Australian Lleyton Hewitt, now ranked five, is the top seed.

In the doubles competition, Prakash and his cousin, Stephen Amritraj, will take on top seeds Rick Leach and Brian Macphie of USA in the first round.

In other action, 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 in straight sets 6-4, 6-3.