Andy Murray's first match since undergoing back surgery in September ended in a straight sets defeat to Jo-Wilfried Tsonga at an exhibition tournament in Abu Dhabi Thursday. The reigning Wimbledon champion went down 7-5 6-3 to the Frenchman, who himself was plagued by injury at the back end of this year. Murray, who has dropped to No. 4 in the rankings, lacked sharpness after his layoff and was broken in the 12th game of the opening set to fall behind. The British star has been training at his base in Florida to prepare for the upcoming season and looked set to even the match up when he gained an early break of service in the second set. But Tsonga hit back with two breaks of his own to wrap up victory in 72 minutes at the Zayed Sports City complex. The courts here are very fast and you have to react quickly, said 26-year-old Murray. Jo was sharper than me today, he served very well. It's always good fun here. It's great preparation for the season as you have to play against the best in the world. The organizers of the Mubadala World Tennis Championship have indeed attracted a stellar field with the top two ranked players, Rafael Nadal and Novak Djokovic, in the line-up. David Ferrer of Spain won the opening match Thursday as he beat Stanislas Wawrinka of Switzerland 7-5 6-1 to set up a semifinal clash against compatriot Nadal. Tsonga's win over Murray has earned him a