Del Potro pulls out of Miami

Key Biscayne, FL ( - Former U.S. Open champion Juan Martin del Potro pulled out of the $4.7 million Sony Open on Wednesday, citing a wrist injury that has bothered him for weeks.

"I still feel pain in my left wrist and I don't feel competitive to go on court," del Potro said. "It's a pity because this is a special tournament for me since there are many Latin fans and Argentines in particular. In the next few days I will visit my doctor again to determine the following steps."

The injury has forced del Potro to either withdraw or retire from his last three events.

The eighth seed was replaced in the 96-player field by German lucky loser Benjamin Becker.

On the court Wednesday, Czech veteran Radek Stepanek eased past German Daniel Brands 6-3, 6-0; Croat Ivan Dodig came back to best Kazakhstan's Andrey Golubev 4-6, 6-1, 6-4; quality Frenchman Julien Benneteau overcame British wild card Kyle Edmund 6-7 (2-7), 6-3, 6-2; capable Frenchman Adrian Mannarino dismissed one-time world No. 3 Russian and 2008 Miami champion Nikolay Davydenko 6-4, 7-5; and talented Frenchman Jeremy Chardy outlasted gritty Argentine Juan Monaco 7-5, 3-6, 7-6 (7-5). Chardy's second-round opponent will be last week's Indian Wells titlist and former world No. 1 star Novak Djokovic.

Also advancing to the second round were Dutchman Thiemo de Bakker, Czech Jiri Vesely, Aussie Marinko Matosevic, Spaniard Albert Montanes, Russian Teymuraz Gabashvili, Colombian Alejandro Gonzalez, and Aussie Matthew Ebden, who is rewarded with a match against reigning Miami champion Andy Murray.

Wednesday's night session featured opening-round wins from 2006 Australian Open finalist Marcos Baghdatis, Croatian veteran Ivo Karlovic, Argentine Horacio Zeballos and Austrian Dominic Thiem.

Karlovic's 7-6 (7-3), 7-6 (7-5) decision over Paul-Henri Mathieu set up a second-round matchup with Roger Federer, a back-to-back Miami champion in 2005 and 2006.

The Sony Open is staged on the hardcourts at Crandon Park and serves as the second ATP Masters 1000 event in two weeks.

The top seeds at this 12-day tournament are Rafael Nadal, the three-time champion Djokovic and Stan Wawrinka. Federer is seeded fifth, while Murray is the sixth seed.

The Wimbledon titlist Murray beat French Open runner-up David Ferrer in last year's Miami finale.

The 2014 winner of this lucrative event will collect $787,000.