LONDON (AFP) - Former US Open champion Juan Martin del Potro enjoyed a winning return to grass as the Argentine beat Uzbekistan's Denis Istomin 6-4, 6-2 in the first round at Queen's on Tuesday. Del Potro was playing his first match on grass since Wimbledon in 2009 after missing most of the 2010 season with a serious wrist injury. The 22-year-old, who last appeared at Queen's back in 2007, is clearly making up for lost time and he has already risen from a lowly ranking of 484 in the world in February to 22nd going into this week. His height and power should make his game ideally suited to the lush lawns of west London and he demonstrated those abilities in the first set, breaking Istomin twice in the first five games. The 6ft 6in Argentine, winner of the 2009 US Open final against Roger Federer.