Novak Djokovic has overcome illness, a mid-match meltdown and an inspired Dominic Thiem to claim a record-extending eighth Australian Open crown.
In a titanic battle laced with controversy and drama, Djokovic overturned a two-sets-to-one deficit for the first time in a grand slam final to deny Thiem a maiden major with a 6-4 4-6 2-6 6-3 6-4 victory on Sunday night.
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Djokovic is the first man in the 52-year open era to win grand slam titles in three different decades, and just the second in history after Ken Rosewall snared majors in the 1950s, 1960s and 1970s.
His 17th career slam also leaves the super Serb just three behind all-time majors leader Roger Federer and propelled the 32-year-old back to world No.1.
But he had to fight tooth and nail - and the chair umpire - for this one as Thiem threatened to shatter Djokovic's aura of invincibility at Melbourne Park.
The flashpoint in the final came after the ninth game of the second set.
Incensed at receiving two time violations on successive points, Djokovic fired a forehand way over the baseline to drop serve to fall behind 5-4 before venting his frustrations at the changeover.
In an ugly exchange that had social media aflutter with calls for the Serb to be disqualified, Djokovic tapped Damien Dumusois on his shoe twice while marching to his chair.
He then sarcastically congratulated the French official.
"You made yourself famous in this match. Great job. Especially in the second one. Great job. You made yourself famous. Well done," Djokovic said before leaving the court for a clothes change after Thiem served out the set.
Perhaps still rattled, and seemingly suffering physically, Djokovic double-faulted on his first serve upon the resumption and quickly slumped to a 4-0 deficit in the third set as Thiem appeared to seize control.
Drama-charged Australian Open final
The titleholder finally snapped a run of six straight games, only to call for the tournament doctor when trailing 4-1, complaining of feeling ill.
Djokovic required more treatment - and a pill - after dropping the set to find himself in deep trouble.
But, displaying the championship qualities that have him challenging Federer and Rafael Nadal as tennis's so-called GOAT - greatest of all time - Djokovic broke Thiem in the eighth game of the fourth set to force a decider.
Runner-up in the past two French Open finals to Nadal, Thiem dropped serve again in the third game of the fifth set as Djokovic surged to a 3-1 lead.
One of the most ruthless finishers in tennis, Djokovic refused to relinquish his advantage, finally subduing Thiem's challenege after three hours and 59 minutes.
In thwarting Thiem's valiant quest to become Austria's first-ever Australian Open champion, the 32-year-old also extended the big three's run of grand slam triumphs to 13 since Stan Wawrinka won the 2016 US Open.
Djokovic, Nadal or Federer have also now won 14 of the past 15 Australian Opens.