World No1 Novak Djokovic took another step towards defending his Indian Wells title with a hard-fought 6-4, 7-6 (7/5) win over American John Isner on Wednesday.

Djokovic has struggled in the past with the 6-foot-10 (2.08m) Isner's bombing serve on the hardcourts of the California desert.

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But the reigning Australian Open champ got the best of his opponent in the key tiebreaker.

Djokovic booked a quarter-final clash with 35th-ranked Bernard Tomic of Australia.

Tomic eliminated fellow Aussie Thanasi Kokkinakis 6-4, 4-6, 6-4.

Djokovic now has a 6-2 advantage in career meetings, with nine of the sets going into tiebreakers. Isner has won six of those, so Djokovic felt fortunate to squeak through this time.

Djokovic hammered seven aces and saved both break points he faced in the one hour, 31 minute match.

Four-time Indian Wells winner Roger Federer needed just 69 minutes to oust American Jack Sock 6-3, 6-2.

In the quarter-finals, the Swiss second seed will face ninth-seeded Czech Tomas Berdych, a 6-2, 4-6, 6-4 winner over compatriot Lukas Rosol.

Federer and Berdych have met 18 times with the Swiss holding a 12-6 lead.

World number three Rafael Nadal rolled over France's Gilles Simon 6-2, 6-4.

The left-handed Spaniard hammered four aces and broke Simon five times to set up a meeting with hard-hitting Milos Raonic of Canada.

Raonic hammered a 241 kmph (150 mph) serve en route to a 6-3, 6-2 straight set win over Tommy Robredo of Spain.

Raonic is in his second straight quarter-final but he will have his work cut out for him because he has never beaten Nadal in five career meetings.

Fourth seeded Andy Murray, trying to rebound from a subpar 2014, defeated Adrian Mannarino 6-3, 6-3 in the fourth round.

Murray next faces Spain's Feliciano Lopez who upset fifth seed Kei Nishikori of Japan 6-4, 7-6 (7/2).