'Bravo': Rafael Nadal's incredible moment with volunteer firefighter

Some of the biggest names in world tennis came together to raise nearly $5 million on Wednesday night in the Rally for Relief fundraiser for bushfire victims.

A full house at Rod Laver Arena watched Roger Federer defeat Nick Kyrgios in a one-set finale to the Australian Open's charity night to aid bushfire appeals.

SHOCK SWIPE: Federer and Nadal slammed over 'selfish' bushfire response

But it was a touching moment involving Rafael Nadal that stood out as the highlight.

Volunteer firefighter Deb was invited onto the court to play some doubles with Nadal - her favourite player.

The CFA volunteer and weekend tennis player has been helping fight fires in Victoria’s northeast.

But on Wednesday night she teamed up with Nadal in a doubles match against Caroline Wozniacki and Alexander Zverev.

Deb showed off some pretty handy tennis skills, hitting a number of winners while playing up at the net.

She even got a huge hug from Nadal after one winner, with the World No.1 crying “Bravo”.

Fans watching at home absolutely loved Deb’s cameo.

Kyrgios and Federer staggered by response

Federer took on Kyrgios as the centrepiece of Wednesday night's event and prevailed 7-6 (8-6).

Stars including Nadal, Serena Williams, Novak Djokovic, Coco Gauff and Stefanos Tsitsipas also played Fast Four doubles at the event that helped to raise almost $5 million.

"I've got goosebumps ... everyone came together and it's just an amazing feeling," Kyrgios said. "It's been an emotional couple of weeks.

"When I was back home in Canberra, I couldn't even go outside (due to bushfire smoke) ... and I'm just so happy that we had Roger, Rafa, Novak - some of the greats - to get behind this.

"The awareness has grown and I think we're doing everything we possibly can to overcome this."

With select firefighters and emergency personnel looking on from courtside seats, Kyrgios saved two set points before Federer prevailed in an entertaining encounter.

The six-time Australian Open champion and world No.3 moved well, ahead of his 20th assault on the season-opening grand slam at Melbourne Park.

But a competitive hit-out wasn't really his goal.

"What I wanted to do was raise awareness, raise money and tell people to still come and travel to Australia because people probably think around the world that you can't right now," Federer said.

"That was the idea.

"And to have some fun, have a hit with Nick ... we get along very well.

"We've had some epic matches over the years and this was fun ... it wasn't about winning and losing."

The Swiss master also dipped into his own pocket, combining with Nadal to make a $250,000 donation, with fundraising efforts to continue during the Australian Open.

with AAP