ABU DHABI, United Arab Emirates -- Andy Murray's 2013 season got off to a shaky start Thursday with a 6-3, 6-4 loss to Janko Tipsarevic in the opening match of the World Tennis Championship exhibition tournament.

Two early breaks in each set helped Tipsarevic dispatch the third-ranked Murray. The Serb next faces Nicolas Almagro, a late replacement for Rafael Nadal who pulled out of the tournament with a stomach bug.  
"It's not every day that you get to play a Grand Slam champion and an Olympic gold medalist," said Tipsarevic, who is ranked No. 9. "I know it's an early-season tournament but I can tell you that the six of us take this very seriously."  
"I knew I could beat Andy as I have beaten him before," he added. "He's a totally different animal now as he won a Grand Slam and Olympic gold so beating him here has given me confidence. Both of us have very similar games so it's great to come out on top."  
In Thursday's other match, fifth-ranked David Ferrer defeated sixth-ranked Tomas Berdych 6-2, 6-4 to set up a semifinal against top-ranked Novak Djokovic, who won the tournament last year. Ferrer easily won the first set after jumping to a 5-0 lead. He broke serve early in the second.  
"I played well today and I was surprised as it has been a long time without playing a competition," Ferrer said. "It's a fast court and this was the first time I played at night but I played a good game. I will enjoy a victory for now, but tomorrow I will have to play my best against Novak."  
Djokovic said winning the French Open -- the only Grand Slam tournament he has yet to capture -- is his top goal of the year.  
"I managed to have the best year of my career in 2011 and I knew that it was going to be difficult in 2012 to maintain No. 1 in the world and play consistently," Djokovic said. "I did, and so this year was an even more successful year from a psychological aspect. ... Ambitions are always high and I want to win every Grand Slam and major tournament I play, and this year is no different."