The Swiss world number two again mastered old rival Nikolay Davydenko in three sets to confirm his match-up with big-talking Tomic, 20, in the last 32 on Saturday.
The record 17-time Grand Slam champion had few problems with the 40th-ranked Russian, winning 6-3, 6-4, 6-4 in 1hr 59min in a night match on Rod Laver Arena. Murray mercifully kept it short as Jo-Wilfried Tsonga and Tomic were made to sweat it out to the third round.
British third seed and reigning US Open champion Murray was impressive in conceding just eight games as he put away 100th-ranked Portuguese Joao Sousa, 6-2, 6-2, 6-4 in 1hr 41min on Hisense Arena.
Tsonga, Del Potro advance
Frenchman Tsonga, a runner-up here five years ago, was made to toil hard for his 6-3, 7-6 (7/1), 6-3 win over Japan’s Go Soeda. Former US Open champion Juan Martin Del Potro bludgeoned a 6-2, 6-4, 6-2 win over German Benjamin Becker, while Gael Monfils double-faulted on four match points before winning 8-6 in the fifth set against Lu Yen-hsun.