The Czech Republic's Tomas Berdych and Britain's Andy Murray moved up one spot each to fifth and sixth, respectively, in the ATP rankings, while Argentina's Juan Martin del Potro fell two slots to No. 7.

The 25-year-old Del Potro reinjured his left wrist at the Dubai Duty Free Tennis Championships last week.

Del Potro had to retire last Tuesday from his first-round match at the hard-court event, which was won by Switzerland's Roger Federer.

The Argentine star, who won the 2009 U.S. Open, missed most of the 2010 season with an injury to his right wrist and had to work his way back into the top 10.

Spain's Rafael Nadal remained at No. 1 in the world, with Serbia's Novak Djokovic at No. 2, Switzerland's Stanislas Wawrinka at No. 3 and Spain's David Ferrer in the No. 4 spot.

Federer, who defeated Berdych 3-6, 6-4, 6-3 in the final in Dubai on Saturday, is at No. 8.

France's Richard Gasquet is the world No. 9 and his countryman, Jo-Wilfried Tsonga, is at No. 10.

The big climber in the top 100 was Brazil's Thomaz Bellucci, who moved up 22 spots to No. 86, while Argentina's Federico Delbonis climbed 17 spots to No. 44 in the world.

Argentina's Leonardo Mayer was the big loser, falling 17 spots to No. 76 this week.

Tommy Robredo, the world No. 17, and Nicolas Almagro, who is ranked No. 19, are the other Spanish players in the top 20. EFE