At the peak of a long-running feud between Novak Djokovic and Nick Kyrgios, the prospect of them ever becoming pals seemed ludicrous.

After all, how could Djokovic warm to someone who he had "not much respect for" off the court?

What could stop Kyrgios thinking the Serb was a "tool" and a "strange cat" with a "sick" obsession for needing to be liked?

Yet here we are, a few years down the line, and the once-squabbling pair are now the best of buddies and making their debut as a doubles team.

Australian firebrand Kyrgios, often polarising but almost always entertaining, promised fun at the Brisbane International.

The pair delivered in front of an enthusiastic sell-out crowd, putting on a show as they secured a 6-4 6-7 (4-7) 10-8 win over Austria's Alexander Erler and Germany's Andreas Mies.

A celebratory chest-bump when they completed victory - on their third match point - was symbolic of a bromance which nobody saw coming.

"That was awesome," said 24-time major champion Djokovic.

"I want to thank Nick for playing. He said it should be a pleasure to play with him, it was a pleasure.

"I'm glad to share the court with him on his comeback."

Their relationship thawed when Kyrgios offered support to Djokovic over a court decision to deport him from Australia in 2022, and has continued to warm ever since.

But, before the match, Kyrgios had little idea how things would pan out.

The 2022 Wimbledon runner-up was back on a competitive court for the first time in 18 months following a wrist ligament injury which he feared would end his career.

How the 29-year-old's body would react was the first unknown.

How a new partnership between "two different personalities" would gel was the second.

"We might get absolutely snipped," said Kyrgios, who lost to Djokovic in the only major final of his turbulent career at Wimbledon in 2022.

Any lingering concerns about Kyrgios' physical state were put to bed with a hold to love in an opening service game which demonstrated he had lost none of his trademark power.

"What a game I played, huh," chuckled Djokovic.

The way in which the pair were laughing and joking illustrated the ease they now feel in each other's company.

The entertainment increased as the set went on, with Djokovic providing two moments worthy of any highlights reel to help tip the opener in his team's favour.

The 37-year-old Serb threaded a stretching backhand through the gap between the net post and the umpire's chair for 15-15 in the 10th game, then brought up a pair of set points with a lob measured to perfection.

Kyrgios converted the first with a superb forehand winner which clipped the edge of the line, sparking joyous celebrations among the crowd.

The match continued to be a tight tussle in the second set - although there was still opportunity for some vintage Kyrgios.

On his serve at 3-3, he produced a trademark tweener and backed it up by putting away a sharp volley.

The smile as he scampered down the line indicated his satisfaction as he lapped up the acclaim from the fans, while a delighted Djokovic raced over to join him in the celebrations.

Erler and Mies locked in to level the match but the superior skillsets of Kyrgios and Djokovic ensured the duo would return for another performance later this week.

"This injury has been brutal for me so I wasn't taking any of this for granted," said Kyrgios.

"I don't know how many Aussie summers I have left.

"We promised we would do this one time before he goes or I go. So I'm glad we're still alive."