The Spaniard and Aussie are vying for a place in the quarterfinals with the winner squaring off against either tenth seed Gael Monfils or fifth seed Dominic Thiem.
Nadal's road to the fourth round
The Spaniard has been largely untroubled, not dropping a set through the first three rounds. Hugo Dellien was dispatched 6-2, 6-3, 6-0 in the first round, Federico Delbonis 6-3, 7-6 (4), 6-1 in round two and 27th seed Pablo Carreno Busta was demolished 6-1, 6-2, 6-4 in the third round.
Kyrgios' road to the fourth round
As always with the Australian, it's been an entertaining and interesting ride. In the first round, Kyrigos knocked off Lorenzo Sonego 6-2, 7-6 (3), 7-6 (1). Round two was a 6-2, 6-4, 4-6, 7-5 victory over Gilles Simon while the third round against 16th seed Karen Khachanov was an instant classic, the 23rd seed prevailing 6-2, 7-6 (5), 6-7 (6), 6-7 (7), 7-6 (8) in four hours, 26 minutes.
This is the eighth career meeting between Nadal and Kyrgios with the Spaniard holding a 4-3 lead. Their last meeting was in the second round of Wimbledon last year with Nadal prevailing in four sets. Kyrgios' last win was also last year in Acapulco on his way to the title.
Who will win?
This is the biggest match of Kyrgios' career. He's playing for a cause, has beaten Nadal before and will have huge crowd support. He's serving really well and has the weapons to hit Nadal off of the court.
The world number one has not lost a set and looks to be rounding into form as evidenced by his performance against Carreno Busta. Just staying solid and making Kyrgios run would probably be enough.
That being said, you can't make up for inspiration and despite everything he has going against him, I think Kyrgios will overcome the odds and produce the finest win of his career.
Prediction: Kyrgios in five sets