Melbourne - World No 1 Rafael Nadal and home favourite Nick Kyrgios will take their feud into the Australian Open fourth round on Sunday after a series of bad-tempered exchanges.
Kyrgios, 24, is seeking his second Melbourne quarter-final and his first Grand Slam title while Nadal, 33, is hunting a record-equalling 20th Major crown.
Bubbling animosity has characterised relations between the two, after Nadal accused Kyrgios of lacking respect and the Australian fired back that the Spaniard was "super salty".
There is also little to split them, with Nadal leading their career head-to-head 4-3 but Kyrgios 2-1 up on hard courts and an even 1-1 in their Grand Slam matches, both at Wimbledon.
The second of those, last year, was a torrid affair, with Kyrgios ranting at the umpire, serving underarm and deliberately firing a forehand at the Spaniard.
However, Kyrgios struck a conciliatory tone before Monday's match, saying there was a "layer of respect" between the two players, despite their differences.
"I don't really dislike him. I don't know him at all. Hell of a tennis player. Don't know him as a person. I'm sure he's okay," he said.
"I'm super-excited honestly. Playing one of the greatest tennis players on centre court at your own Slam, it's pretty damn cool."
Either Nadal or Kyrgios will go into a quarter-final against Dominic Thiem, the Austrian fifth seed.