Ruthless Rafael Nadal continued his relentless progress to reach the last four of the Australian Open as he slayed giantkiller Frances Tiafoe 6-3, 6-4, 6-2 on Tuesday.

Unseeded Tiafoe, 21, had shocked fifth seed Kevin Anderson and Grigor Dimitrov, seeded 20, but the 17-time Grand Slam champion proved too formidable for the popular American in his first major quarter-final.

The Spanish number two seed sprinted through in 107 minutes and will face another emerging star, the 20-year-old Greek sensation Stefanos Tsitsipas in the semi-finals.

“I had some trouble at this event all my career so I am very happy with the way I played tonight,” said Nadal, who retired from last year’s quarter-final injured against Marin Cilic.

The Spaniard has been in irresistible form in Australia in his first tournament since limping out of the US Open and having foot surgery.

“I feel lucky to be where I am after what I went through to be able to compete at this level,” he said.

“That’s why I get up in the morning and go to the gym and work hard.”

Nadal had never faced the world number 39 before but decided rather than feel his way into the match he would bludgeon Tiafoe from his path.

An immediate break of serve was the result and a controlled romp to the opening set in 31 minutes as he imposed his authority.

He repeated the lesson at the start of the second, continuing a game plan that seemed to be based on overpowering the young speedy pretender by keeping him pinned to the baseline.

Tiafoe was bidding to be the youngest American man to make the semi-finals since Andy Roddick in 2003.

The problem was that Tiafoe, who turned 21 on Sunday, was up against the only player in the draw not to have dropped a set.

He finally forced chances to break at 1-2 in the second set, but Nadal twice held out to keep up an amazing run of not dropping his serve since 5-3 up in third set of his first round tie against James Duckworth.

He broke Tiafoe again in the first game of the third set to end any fading hopes that the American could mount a comeback.

If Nadal wins his 18th Grand Slam title in Melbourne to move two behind Roger Federer he will create his own slice of history.

His second Australian Open crown would make him the first man in the Open-era, and only the third of all-time along with Roy Emerson and Rod Laver, to win each Grand Slam on two or more occasions.