By Simon CambersROME (Reuters) - Andy Murray battled back from a break down in the final set to beat Argentina's David Nalbandian in the second round of the Rome Masters tennis on Tuesday.The world number four, a semi-finalist here last year, romped through the first set but trailed 3-1 in the third before rallying for a 6-1 4-6 7-5 victory in more than two-and-a-half hours.In a testing wind and with the sun dropping behind the stands of the main stadium at the Foro Italico, Murray looked on course for a simple win on his 25th birthday when he romped through the first set.However, Nalbandian, ranked 42 but once as high as third, used the drop shot and angled groundstrokes to great effect to level the match and then go up 3-1 in the decider.Immediately, Scot Murray broke back and then, at 5-5, took his third breakpoint chance to lead 6-5 before saving two break-back points to reach round three.Sixth seed David Ferrer saw off fellow Spaniard Fernando Verdasco 6-3 7-6 and Gael Monfils, seeded 13, was beaten 7-5 6-3 by former world number one Juan Carlos Ferrero.Defending women's champion Maria Sharapova came through a tough test by American world number 36 Christina McHale before winning 7-5 7-5 to reach the third round.The Russian trailed 4-1 and 5-3 in the opener before hitting back to take the set and then held off a spirited challenge from the 20-year-old McHale before squeezing through.After the slippery clay of last week's Madrid Masters, the players had to cope with gusting winds which disturbed their fluency."It was really about adjusting from Madrid," Sharapova told a news conference after setting up a third-round clash with either Ana Ivanovic of Serbia or Spanish qualifier Silvia Soler Espinosa."I made a few too many unforced errors at first and maybe I was going for too many lines but she was extremely consistent."I was a bit lucky to get out of the first set and the second set was close but she's definitely improved since the last time I played her. I'll have to improve in the next round too."Wimbledon champion Petra Kvitova survived a tough match with Anastasia Pavlyuchenkova of Russia, recovering from a slow start to advance 7-5 6-4.Former world number one Venus Williams, in her fourth tournament back since she was diagnosed with the energy-sapping Sjogren's Disease, reached round two with a 6-3 6-4 win over Simona Halep of Romania.(Editing by Clare Fallon)