Tomic can't end Rafa's run

Rafael Nadal dashed the hopes of rising Australian star Bernard Tomic to take another step on the road to the "Rafa Slam".

Tomic impressed, and could have claimed a set off the world number one had he not taken his foot off the gas at 4-0 up in the second, but Nadal eventually cruised home 6-2 7-5 6-3 in two-and-a-half hours on Rod Laver Arena.

While 18-year-old Tomic will benefit from the experience in the long-term, Nadal has a more immediate goal as he bids to become the first man since Rod Laver in 1969 to hold all four grand slam titles simultaneously. He will now play 15th-seeded Croatian Marin Cilic, who beat John Isner in a marathon five-setter.

Robin Soderling and Andy Murray remained on course for a quarter-final showdown after both recorded straightforward victories.

Soderling cruised past Jan Hernych 6-3 6-1 6-4 while Murray thrashed hapless Spaniard Guillermo Garcia-Lopez 6-1 6-1 6-2.

Number five seed Soderling will have to see off rising young Ukrainian star Alexandr Dolgopolov while Murray meets 11th seed Jurgen Melzer.

Dolgopolov avenged his five-set loss to Jo-Wilfried Tsonga at Wimbledon last year with a 3-6 6-3 3-6 6-1 6-1 win and the Frenchman, seeded 13, had no complaints.

Melzer got the better of popular Cypriot Macros Baghdatis. The Austrian was 6-7 (5/7) 6-2 6-1 4-3 up when Baghdatis withdrew with a right finger injury.

Seventh seed David Ferrer made smooth progress but 10th seed Mikhail Youzhny was stunned by the big-serving Milos Raonic, the Canadian winning 6-4 7-5 4-6 6-4.

Raonic will now meet Ferrer following his 6-2 6-2 6-1 demolition of Lithuanian Richard Berankis.