LONDON (Agencies) - David Ferrer pulled off the first upset of the ATP World Tour Finals by defeating Andy Murray 6-4, 7-5 Monday. In the opening match of Group A, Ferrers consistency proved too much for the third-seeded Murray, who had treatment for an apparent hip injury between sets. The seventh-seeded Spaniard broke in the 10th game of the first set and twice came from a break down in the second to stun Murray and the home crowd inside Londons O2 Arena. Murray finished with 44 unforced errors and made just 46 percent of his first serves. Later Monday, top-ranked Novak Djokovic was hoping his shoulder injury would hold up in his opening match against Tomas Berdych of the Czech Republic. His loss was all the more surprising given the 24-year-old Scot had won all five of his previous matches on hard courts against Ferrer and came into the tournament with a 17-1 record since losing in the U.S. Open semifinals to Nadal. Murray broke for a 2-1 lead in the first set but then immediately conceded the advantage with an error-strewn game. And while Murrays form fluctuated wildly, Ferrer maintained his trademark consistency from the baseline. Murray hadnt shown any sign of an injury but when serving to stay in the set at 5-4 down, he asked the umpire to call for the trainer and subsequently dropped serve for the second time, blazing a forehand long and wide on Ferrers second set point. The trainer gave Murray a vigorous massage during the injury time-out, and it seemed to have done the trick when Murray immediately broke serve in the second setalbeit thanks to a rare error by Ferrer. The stadium was about two-thirds full for the afternoon session, despite the appearance of the only British player in the tournament. Murrays performance didnt give them much to cheer about as he lost serve at love in the fourth game and double-faulted to give up another break in the eighth. Ferrer found his best form just when it counted. Leading 6-5, the Spaniard punched a perfect volley onto the sideline to bring up match point, and pounced on an ill-advised drop shot from Murray to take control of the point and claim his first win at the O2 Arena after going 0-3 last year. Murray will hope his body can recover quickly as he will face the loser of the Djokovic-Berdych match on Wednesday, needing a win to maintain any chance of reaching the semifinals.