INDIA WELLS; Croatian Ivan Ljubicic ousted a weary World No 2 Novak Djokovic 7-5, 6-3 on Wednesday as defending champion Rafael Nadal booked his quarter-final berth at the BNP Paribas Open.

While third-seeded Nadal advanced with a 7-5, 3-6, 6-3 win over big-serving American John Isner, Djokovic couldn’t keep pace with the blistering serves and clean groundstrokes of Ljubicic, a former world No 3 now ranked 26th in the world. World No 4 Andy Murray secured his quarter-final slot with ease as Spain’s Nicolas Almagro retired while trailing with an apparent left ankle injury. Murray led 6-2, 1-0 when Almagro called it quits after receiving treatment on court at the end of the first set.

Ljubicic said he was delighted to end a five-match skid against Djokovic, calling some of those defeats “brutal”. The tournament has now lost top two men’s seeds, after World No 1 Roger Federer was stunned by Marcos Baghdatis in the third round on Tuesday. That left Spain’s Nadal as the highest-ranked player to make it into the quarter-finals as he withstood a barrage of 22 aces from the 24-year-old American Isner. Nadal closed it out with a forehand winner into an open court.

Nadal next faces Czech Tomas Berdych, a 6-1, 6-3 winner over Serbian Victor Troicki, while Ljubicic will take on Argentina’s Juan Monaco, who beat Spain’s Guillermo Garcia Lopez 3-6, 6-2, 6-1. Baghdatis couldn’t hold off Spain’s Tommy Robredo, who notched a 7-5, 0-6, 6-4 victory to line up a meeting with seventh-seeded American Andy Roddick, who beat Austraia’s Jurgen Melzer 7-6 (7/5), 6-4. Murray will play sixth-seeded Swede Robin Soderling, who beat France’s Jo-Wilfried Tsonga 6-3, 6-4.

On the women’s side, second-seeded Caroline Wozniacki saw off the tenacious challenge of Zheng Jie to book a semi-final showdown with good friend Agnieszka Radwanska. Denmark’s Wozniacki stepped it up in the third set to beat Zheng 6-4, 4-6, 6-1, claiming her first victory over the Chinese player in three attempts.

Radwanska, the fifth seed from Poland defeated fourth-seeded Russian Elena Dementieva 6-4, 6-3, denying Dementieva a shot at a third title of the season after her victories in Sydney and the Paris Indoors. Wozniacki, whose parents are Polish, is a close friend of Radwanska. She said the two talk make-up and fashion and boys when they go out to dinner together, but will keep it businesslike on the court.