Del Potro pulls out of Sony Open

World No. 8 Juan Martin del Potro withdrew from the Sony Open on Wednesday with a left wrist injury that has plagued him since the Australian Open in January.

The ailing wrist forced Del Potro to retire from a first-round match against Somdev Devvarman at the Dubai Duty Free Tennis Championships two weeks ago. He also did not compete at last week's BNP Paribas Open in Indian Wells, Calif.

In first-round Sony Open men's action, 80th-ranked Adrian Mannarino of France ousted 71st-ranked Nikolay Davydenko of Russia 6-4, 7-5.

Czech Radek Stepanek defeated Daniel Brands of Germany 6-3, 6-0.

Ivo Karlovic of Croatia picked up a tough 7-6 (3), 7-6 (5) win over French qualifier Paul-Henri Mathieu.

Information from The Associated Press was used in this report.