Tickets for the fifth edition of the FAST4 Showdown are now on sale, with Grigor Dimitrov and Milos Raonic confirming they will join ardent adversaries Nadal and Kyrgios at the Showdown, which will take place at Qudos Bank Arena on Monday, January 7.

Battle lines between Nadal and Kyrgios were drawn for the first time at the All England Club in 2014, when Kyrgios became the first Wimbledon debutant in a decade to beat an incumbent No.1, winning a four set, fourth-round thriller over the Spaniard that rocked the tennis world to its foundations.

Since that clash the pair has met a further four times on the ATP World Tour, with Nadal holding a 3-2 head-to-head advantage, but Kyrgios won their only previous FAST4 meeting, at Sydney’s 2017 Showdown.

"I’m really looking forward to playing in Sydney again in January," Nadal said.

"There was an amazing turnout for the FAST4 Showdown last time I played, and the fans loved the tennis and really got involved with the matches.

"It’s been a couple of years since I’ve played in Sydney, so I’m looking forward to going back there, playing for the fans."

Kyrgios will be playing his third consecutive FAST4 Showdown when he takes to the court at Qudos Bank Arena in January.

"I didn't think the level was going to be that high," Kyrgios said after charging to an impressive four set win over Nadal at the 2017 FAST4 Showdown.

"But I don't think Rafa knows any other way than to go out there and give 100 per cent. We weren't taking it easy at all."

Tennis NSW CEO Lawrence Robertson added, “FAST4 is an exciting and engaging format for the fans and the players, and there’s always a great atmosphere on court during matches.

“Add Rafa, Nick, Grigor and Milos – four of the biggest names in world tennis today – into the mix and I know we’ve got a massive night of action and entertainment to look forward to."

FAST4 Tennis is a modified tennis format launched globally in Sydney in 2015 by Roger Federer and Lleyton Hewitt.

The fundamentals of the game remain the same with four innovative rules to ensure tennis matches are fast, competitive, exciting and can be completed in a short period of time.

Players play lets, no ad scoring, a tiebreak is played at three games all and the first to four games wins.