Aiming for a record-extending eighth title in Melbourne, defending champion Djokovic took the first set 6-4.

But amid a feisty atmosphere on Rod Laver Arena from both Djokovic and Thiem fans, the Serb saw tensions spill over in the ninth game when he claimed a point to move 30-0 up.

As Djokovic and Thiem traded shots from the baseline the Austrian sent a shot into the tramlines, but Djokovic appeared furious that a fan had made a noise during the rally.

"Shut the f**k up!," the 16-time Grand Slam winner appeared to mouth aggressively at fans in the crowd.

It wasn’t the only time the fiery Serb lost his cool, as during the second set he clashed with umpire Damien Dumusois after being given a time violation for not serving quickly enough.

Djokovic sarcastically tapped Dumusois  on the shoe as he made his way to the chair between games, muttering: “You made yourself famous. Well done man. Mission accomplished.”

Thiem battled back to take the second and third sets amid a febrile atmosphere, as an out-of-sorts Djokovic appeared to struggle with health issues, calling out the doctor during the third set.  

But ever the warrior, Djokovic then fought back to win the fourth set 6-3 and take things to a decider as an epic unfolded under the lights in Melbourne.