Indian Wells, California  - Andy Murray had his difficult moments before managing to snuff the candles on the 30th birthday celebrations of opponent Ivan Ljubicic 7-5,
7-6 (8-6) in the quarter- finals of the Indian Wells Masters on Thursday.

Fourth seed Murray denied the Croatian many happy returns on court with the battling victory in just over two hours, to set up one-half of a potential dream semi-final in California. . Murray was awaiting the winner from an evening meeting between second seed Roger Federer, who was facing Australian Open semi-finalist Fernando Verdasco.

Murray has beaten Federer three times since losing the US Open final to the Swiss six months ago, and also stands 3-0 in their three meetings at the Masters 1000 level.

The 74th-ranked Ljubicic put Murray under constant pressure in their quarter-final, refusing to roll over as the Scot took leads.

The veteran broke Murray back in the second set for 5-5 and then stole a 6-5 lead in a game concluded with a pair of thundering aces, his fifth and sixth of the afternoon at the Tennis Garden.

Murray answered with a love game for 6-6 to send the set into a tiebreaker, with Ljubicic saving a match point in the decider before finally falling as he played a quarter-finals in the desert for the third time in the past four years.

Lujbicic had saved five match points a day earlier in his win over Russian Igor Andreev.

Earlier, women's defending champion Ana Ivanovic secured free passage into the final four when opponent Sybille Bammer withdrew with a left shoulder injury.

The walkover puts the fifth-seeded Serb into a semi-final against breakthrough Russian teenager Anastasia Pavlyuchenkova, who knocked out Polish seventh seed Agnieszwa Radwanska 7-6 (10-8), 6-4.

"I'm very disappointed that I am not able to play," said Austrian Bammer, who added: "Tonight, I make an MRI, and I will check my shoulder and I will rest and I hope I am fine for Miami.

"I normally play very well here and it is a place I really enjoy. I was playing better and better every round, and had a good feeling about today's match.

"Unfortunately, my shoulder injury is making it impossible for me to play. I hope that the injury heals quickly and that I am able to return to action soon."

Pavlyuchenkova, ranked 42nd, was playing in her third quarter- final of the season after Sydney and Paris and has never advanced this far at the WTA level.

"I'm very excited now, and more and more every day because I keep winning," said the Russian, who beat second seed Jelena Jankovic in the second round last week.

"It's really big achievement for me this week. I beat some really good players.

"I'm very happy, especially today. It's my first time in semis. I've played Agnieszka five or six times already. She's a very tough player for me. I'm very happy I went through," said Pavlyuchenkova. dpa