INDIAN WELLS (California) (AFP) - World number two Roger Federer battled past Fernando Verdasco 6-3, 7-6 (7/5) on Thursday to book a semi-final meeting with Andy Murray at the Indian Wells hardcourt tennis tournament. World number four Murray spoiled Ivan Ljubicic's 30th birthday celebrations with a 7-5, 7-6 (8/6) victory over the Croatian. Federer, playing his first tournament since losing a five-set final to Rafael Nadal at the Australian Open, looked to be cruising when he took a 4-1 lead in the second set. But the four break points he saved in the third game foreshadowed trouble to come. Verdasco finally capitalized on his chances against Federer's serve, breaking him twice to take a 6-5 lead. "I don't think I served great in those games, and I think he got some good hits in," Federer said. "I think he knew that was his last chance, that he had to play well and not make mistakes, and he was able to deliver." But the 10th-seeded Spaniard failed to convert two set points in the 12th game as Federer broke him to force the tiebreaker. Federer took a 6-2 lead in the decider, but still needed four match points to put Verdasco away. "I don't think I deserved that second set," said Federer, who struggled with the rhythm of his backhand. "I wasn't quite happy with the match today, but for a while there I actually was playing OK," he said. Murray needed just over two hours to subdue Ljubicic, who had saved five match points in his win over Igor Andreev a day earlier. Ljubicic said Murray's solidity on serve made the difference. The Croatian led 5-4 in the second-set tiebreaker, but Murray won the next two points on his own serve, then claimed the victory on his second match point. "He served on 5-4 for me, I was not able to put the ball in play," Ljubicic said. "That was probably the most important moment of the tiebreak. I felt like I had chances if the rally would begin. "Again, great serve on 7-6 (for Murray). I managed to put the ball back, but he just controlled it all the way." Murray broke Ljubicic for a 5-4 lead in the second set, in a game in which the Croatian was irked by an electronic replay call on break point. "It's just human mistake," said Ljubicic, who said the Hawkeye replay operator selected the second bounce of the ball to review rather than the first, which was clearly wide. Ljubicic was in position to play the ball, but let it go when he saw it land and the linesman called it out. Murray, who said he couldn't see well from his position on the other side of the net, challenged, and the overrule on review sparked an outburst from Ljubicic. They played a let, but he remained rattled and dropped his serve, although he broke back to take the set to the tiebreaker. "I got lucky on that point," admitted Murray, but added: "I don't know whether it had a huge bearing on the outcome." Murray, 21, has won two titles this year, defending his title at Doha and defeating world number one Nadal in the final at Rotterdam. But he has been troubled by an an ankle injury, and withdrew after reaching the quarter-finals in Dubai with a virus, which also kept him out of Davis Cup. He admitted he was a bit surprised to find himself in the semis after his patchy preparation. However, Murray boasts a 5-2 career record against Federer. Since falling to Federer in straight sets in the US Open final in September, Murray has beaten him three straight times - at Madrid, at the Masters Cup in Shanghai and in Doha. "I'm aware that he has beaten me more than I've beaten him, but on big occasions, I think I came through," Federer said. "I have to build on that and make sure I play tough and play a good match against him." In the remaining quarter-finals on Friday, Nadal will take on sixth-seeded Argentinian Juan Martin del Potro while defending champion and third seed Novak Djokovic of Serbia clashes with seventh-seeded American Andy Roddick. In women's semi-finals, defending champion Ana Ivanovic of Serbia faces 17-year-old Russian Anastasia Pavlyuchenkova, who upset seventh-seeded Agnieszka Radwanska 7-6 (10/8), 6-4. Ivanovic, seeded fifth, advanced on a walkover when Austrian Sybille Bammer pulled out with a shoulder injury. Fourth seeded Russian Vera Zvonareva will face eighth-seeded Victoria Azarenka of Belarus - her doubles partner - in the other semi-final.