Dominic Thiem has avenged back-to-back French Open final losses to Rafael Nadal, shocking the world No. 1 to reach the last four at the Australian Open for the first time.

The Austrian fifth seed gave Nadal a taste of his own medicine at Melbourne Park, out-grinding the Spaniard 7-6 (7-3) 7-6 (7-4) 4-6 7-6 (8-6) in a dogfight that lasted more than four hours.

With the temperature gauge still reading 31C on Rod Laver Arena when the first ball was struck, it was always going to be a war of attrition.

After losing a gruelling opening set, Nadal was incensed when chair umpire Aurelie Tourte slapped him with a time violation while serving at 3-4 after a lengthy point.

"It is really amazing after this point that you put the chrono straight. It is really amazing," he fumed at umpire Aurelie Tourte.

"You don't like the good tennis. You don't like the good tennis."

Nine commentator Jim Courier agreed with Nadal's blow up. "The chair umpire is the one who decides when that shock clock starts. It is when she calls the score. What Nadal is saying is 'you should recognise how much exertion we put into these two points and give us some leeway' and he's right," Courier said.

Nadal then had words with a tournament official to voice his displeasure over Tourte's intervention.

Although Thiem later said he was sympathetic of Nadal's cause after such an energy-sapping point, the Spanish great wasn't keen to talk about the incident.

"No view. That's a time violation, that's all," Nadal curtly told reporters.

Rafael Nadal talks with the chair umpire during his quarterfinal match against Dominic Thiem. Photo / AP

On the wrong end of a 4-9 career record, Thiem had never beaten Nadal in a grand slam after finishing runner-up to him in the past two Roland Garros deciders.

Thiem's thrilling five-set loss to the 19-time major champion at the 2018 US Open was still fresh in his mind as he basked in Wednesday night's breakthrough victory over Nadal.

Except this time he felt the rub of the green went his way.

"We already had this epic match in New York two years ago," Thiem said. "Today, I had really good feeling I was lucky in the right situation. (The) net court was really on my side.

"It's necessary because he's obviously one of the greatest of all-time. You need some luck to beat him."

But lady luck could only carry him so far, with Thiem stumbling as he battled mentally to put Nadal away while serving for the match at 5-4 in the fourth set. "It's a little bit demons in the head," he said.

"Like Roger (Federer) said, it's true. Everybody has it. I was rushing way too much.

"Of course it's very tough to handle if you are up 5-4 against Rafa."

Thiem reached his fifth major semifinal but first somewhere other than at the French Open, the place that is Nadal's domain.

Dominic Thiem celebrates after defeating Rafael Nadal. Photo / AP

Of more significance: The outcome ended Nadal's career-best streak of making at least the semifinals at seven consecutive Grand Slam tournaments, a span during which he earned three trophies.

"He's playing with a lot of energy ... (and) determination. So well done for him," Nadal said. "I honestly didn't play a bad match."

The defining statistic: Thiem won exactly twice as many points that featured nine or more shots, 24-12.

"Just an unbelievable match. Like, epic," Thiem said. "A very high level from both of us."

Having initially built his reputation on clay, Thiem has never been into the final four of a major outside of Paris.

But the 26-year-old's hardcourt game has come on leaps and bounds, emphasised by his title at Indian Wells last year.

Thiem will now meet German Alexander Zverev, another top-10 star long-touted as a grand slam champion in waiting, for a place in Sunday's final. "For me, it's funny because it's first time in a grand slam semi-final I face a younger guy," he said.

"We're good friends. We have no secrets from each other. We (have) played so many times, also on very special occasions already, at the ATP Finals, semis, French Open quarters.

"It's a nice rivalry we have. It's great that we add an Australian Open semi- final."