Novak Djokovic's hamstring just about held up as the hot favourite reached the Australian Open last 16 on Saturday, while Andy Murray's heroic run ended in typically defiant style.

An ailing Djokovic had heavy strapping and needed treatment twice on his troublesome left hamstring before defeating Grigor Dimitrov 7-6 (9/7), 6-3, 6-4 at the Rod Laver Arena.

The Serb will face home hope Alex de Minaur for a place in the quarter-finals as he closes on a 10th Melbourne Park crown and a record-equalling 22nd Grand Slam title.

"Obviously, I didn't know how I'm going to feel physically, it was going up and down," said Djokovic.

"It was an incredible battle, three sets over three hours. Let's rest up and prepare for the next one."

Djokovic's fellow 35-year-old Murray will not join him in the next round, after the Briton's 4:05 am finish in round two eventually caught up with him.

Former number one Murray was clearly feeling the effects of his epic five-setter, which started on Thursday but ended in the early hours of Friday.

The 24th-seeded Spaniard Roberto Bautista Agut won 6-1, 6-7 (7/9), 6-3, 6-4 and faces unseeded Tommy Paul of the United States in the last 16.

Murray admitted having "mixed emotions", saying: "I gave everything that I had the last three matches – I'm very proud of that.

The three-time major champion added: "I'm also disappointed because I put loads of work into the beginning of this year and was playing well enough to have a really good run, have a deep run. I can have a deeper run than the third round of a Slam, there's no question about that."

Also in the men's draw, fifth seed Andrey Rublev surged into a clash with Holger Rune. The Russian crushed Briton Dan Evans 6-4, 6-2, 6-3 to make the fourth round for a third time.

He will face Danish teenager Rune for a place in the quarter-finals after the ninth seed survived a nasty fall to sweep past unseeded Frenchman Ugo Humbert 6-4, 6-2, 7-6 (7/5).

In two all-American matches, Jeffrey Wolf strolled past Michael Mmoh in three sets while Paul made equally light work of Jenson Brooksby. (AFP)