Australia’s Nick Kyrgios falls as he attempts to return a shot to Rafael Nadal during their fourth-round singles match at the Australian Open in Melbourne, Australia, today. (AP photo)

MELBOURNE, Australia — Rafael Nadal left the muttering and the preening, the underarm serving and the ‘tweening, to his younger, flashier opponent, Nick Kyrgios.

Surely, Nadal was content to collect the win in the latest installment of their rivalry.

The No. 1-ranked Nadal kept his thoughts to himself and limited his shot-making to the more traditional variety in an entertaining 6-3, 3-6, 7-6 (8-6), 7-6 (7-4) victory over home-crowd favorite Kyrgios today to reach the Australian Open quarterfinals and get closer to a record-tying 20th Grand Slam title.

“What can I say again about Nick? When he is playing like today, with this positive attitude, he gives a lot of positive things to our sport. So I encourage him to keep working like this,” Nadal said. “Honestly, he is one of the highest talents that we have on our tour.”

Here’s how the elevated stakes and tension affected both men: At 5-all in the pivotal third-set tiebreaker, Kyrgios double-faulted. That offered up a gift-wrapped set point. But Nadal failed to take advantage because he double-faulted right back.

Still, two points later, the 23rd-seeded Kyrgios put a forehand into the net, and the set was Nadal’s. Not long after, Kyrgios double-faulted again to get broken at love.

That put Nadal ahead 2-1 in the fourth, seemingly in charge.

“Against Nick,” Nadal would say afterward, “you are never (in) control.”

Sure enough, Nadal faltered while serving for the win at 5-4, double-faulting to create a pair of break points, the second of which Kyrgios converted with a jumping forehand and celebrated by throwing his head back and screaming. Spectators rose and roared and waved their Australian flags in support of the 24-year-old from Canberra.

But he regrouped and pulled the win out in the closing tiebreaker, which ended with Kyrgios putting a forehand into the net.