An audacious under-arm ace and the second-fastest serve in tennis history were not enough to spare Nick Kyrgios from a fiery second-round loss to Rafael Nadal.

In a gripping Wimbledon encounter that exceeded all the hype, Nadal avenged his stunning defeat to Kyrgios at the All England Club five years ago with a pulsating four-set triumph on Friday morning.

Living up to its grudge-match-of-the-year status, Nadal resisted the volatile Australian’s spirited challenge with a 6-3 3-6 7-6 (7-5) 7-6 (7-3) victory in a three-hour-and-three-minute classic.

Ashleigh Barty earlier barely raised a sweat as she stormed into the third round with a crushing 6-1 6-3 victory over Alison Van Uytvanck.

John Millman also marched into the Wimbledon third round with a commanding 6-3 6-2 6-2 win over Serbian Laslo Djere and will next face American Sam Querrey, while a frustrated Alex de Minaur lost a three-and-a-half hour epic to Steve Johnson of the United States 3-6 7-6 (7-4) 6-3 3-6 6-3.

Ahead of the Kyrgio-Nadal match, a series of verbal jousts between the two – chiefly the Australian’s taunting of the “super salty” Spaniard and Nadal’s “idiot” Uncle Toni in an explosive podcast – had dominated the build-up.

But such testy barbs served as merely the appetiser to a spicy main course that had Wimbledon’s centre court crowd – and the umpire – on the edge of their seats.

Nadal shakes hands at the net with Kyrgios after their often testy match. Photo: Getty

Raging after losing a challenge on his first serve in the eighth game, Kyrgios promptly smashed down an unstoppable, untouchable second serve clocked at 143mph (230kph).

Only Ivo Karlovic’s 144mph (232kph) effort at the 2007 Legg Mason Classic has ever topped Kyrgios’s rocket serve, according to ATP statistics.

The sport’s most unpredictable talent quickly followed up with an under-arm ace, which brought a smile from even the fiercely intense Nadal.

Wimbledon’s famously conservative fans had never seen anything like it, and the daring tactic appeared to briefly unsettle Nadal.

When Centre Court met the underarm ace…

We all knew this was coming, didn’t we?#Wimbledon | @NickKyrgios pic.twitter.com/0gzovjH4bp

— Wimbledon (@Wimbledon) July 4, 2019

The world No 2 Spaniard uncharacteristically sliced a backhand long on the very next point and, although he held to take the opening set, Nadal dropped serve for the first time two games later.

Re-energised, Kyrgios charged to a 4-1 advantage only to be broken to love and then engage in an animated exchange with the chair umpire.

Upset at Nadal’s notorious go-slow antics, Kyrgios demanded French official Damien Dumusois enforced the shot clock on the 18-times grand slam champion.

When he did, an unimpressed Nadal immediately dropped serve as Kyrgios levelled the blockbuster up at one set apiece.

Respect.#Wimbledon | @RafaelNadal | @NickKyrgios pic.twitter.com/VPEXttuRfo

— Wimbledon (@Wimbledon) July 4, 2019

Not content with Dumusois’s intervention, Kyrgios walked a fine line when he branded the umpire a “disgrace” midway through the third set.

Kyrgios then riled Nadal when he speared a forehand into the advancing Spaniard’s midriff.

It was the second time in the match Kyrgios had taken aim at his opponent.

“It certainly wasn’t a passing shot, was it? He had time for a passing shot and he went for the head,” Australian commentator Todd Woodbridge said on BBC TV.

Nadal whipped the crowd into a frenzy when he celebrated winning the vital third-set tiebreaker.

The two-time champion was plain delirious when he finally subdued Kyrgios, who thundered down 29 aces, after another breaker to book to a last-16 meeting on Saturday with Jo-Wilfried Tsonga.

World No 1 Barty earlier needed less than an hour to cast aside Van Uytvanck to extend her winning streak to 14 matches and further fuel hopes of landing back-to-back majors.

Ashleigh Barty shakes hands after winning her game versus Alison Van Uytvanck. Photo: Getty

Barty next plays either British wildcard Harriet Dart or Brazilian qualifier Beatriz Haddad Maia on Saturday with a huge opportunity to embark on another deep grand slam run.

Two matches into her campaign and the French Open champion’s draw is already opening up like it did in Paris.

The shock first-round exits of 2017 Wimbledon champion Garbine Muguruza and world No 22 Donna Vekic have left the Queenslander with a seed-free passage through to at least the second week.

Swiss 13th seed Belinda Bencic looms as Barty’s highest-ranked possible last-16 opponent before a potential heavyweight quarter-final showdown with either seven-time champion Serena Williams or German titleholder Angelique Kerber.

-with AAP