Spain's Rafael Nadal celebrates after winning the men's singles quarter-final match against Canada's Denis Shapovalov

Melbourne (AFP) - Rafael Nadal dug deep into his immense reserves of resilience for the second match running to keep his dream of a 21st Grand Slam title alive at the Australian Open on Tuesday, as women’s top seed Ashleigh Barty powered into a semi-final against Madison Keys.

The ruthless world number one Barty dismantled Jessica Pegula 6-2, 6-0 in 63 minutes to reach the last four at Melbourne Park for only the second time.

“That was solid tonight. I had a lot of fun out here,” said Barty, who is edging closer to becoming the first Australian woman to win her home Grand Slam since Chris O’Neill in 1978.

"That was solid": Ashleigh Barty powers past Jessica Pegula

She will face the unseeded Keys for a place in Saturday’s final after the American, ranked 51, upset French Open champion Barbora Krejcikova 6-3, 6-2.

Wimbledon champion Barty is yet to drop a set and has only given up 17 games in her five matches at Melbourne Park.

Nadal, 35, raced to a two-set quarter-final lead against Denis Shapovalov but then began to feel unwell, needing medical attention for a stomach complaint before surviving a four-hour thriller 6-3, 6-4, 4-6, 3-6, 6-3.

He will face Matteo Berrettini in the semi-final after the Italian seventh seed endured a rollercoaster five-setter of his own to overcome Gael Monfils of France 6-4, 6-4, 3-6, 3-6, 6-2.

The Spanish sixth seed previously had to show all his experience and tenacity just to reach the quarter-final in an epic fourth-round 28-minute tiebreak against Adrian Mannarino, and he somehow found the willpower again to cross the finish line, despite being badly hampered.

A frustrated Shapovalov smashed his racquet after losing and battled with the chair umpire over Nadal's serve time, at one point calling the official "corrupt"

“I started to feel not very well in my stomach so I just asked if they could do something,” said Nadal.

“They just checked everything was all right and then I took some tablets to try to improve the situation. It was lucky that I was serving great in the fifth.”

- ‘A present of life’ -

Nadal won a warm-up tournament and continues to amaze even himself after being out for most of 2021 with a chronic foot injury. He then caught Covid-19 in December.

“I’m not 21 anymore!” he said.

“The real truth is that two months ago we didn’t know if we will be able to be back on tour at all,” Nadal admitted.

“It’s just a present of life that I am here playing tennis again.”

A frustrated Shapovalov smashed his racquet after losing and had a running battle with the chair umpire over the time Nadal was taking to serve, at one point calling the official “corrupt”.

Berrettini later grabbed a slice of tennis history by becoming the first Italian man to reach the last four at the Australian Open.

The seventh seed took the first two sets before the never-say-die 35-year-old Monfils roared back using all his guile and experience to take the match to a decider.

Berrettini found new reserves of energy at the start of the fifth set, powering to a double break that enabled last year’s Wimbledon finalist to surge clear and seal the match in 3hr 49min.

History man: Matteo Berrettini celebrates becoming the first Italian man to reach the semi-finals at the Australian Open

“I was really happy with myself, it was a great fight with Gael, a great match, a lot of emotions,” said the 25-year-old.

“I thought I had him in the third set but then I found myself in the fifth. I really fought hard and I put everything into the court.”

Earlier, Keys continued her impeccable start to the 2022 season with a straight-sets destruction of fourth seed Krejcikova, who needed medical attention after being affected by the heat as the mercury topped 30 Celsius (86 Fahrenheit) during the first set.

Keys was a semi-finalist in 2015 but endured a terrible 2021 where she tumbled down the rankings.

“It means a lot,” she said. “Last year was really hard.”

Madison Keys put the heat on Barbora Krejcikova

Keys said she had to reset completely for the new campaign – and it clearly worked.

She won an Adelaide warm-up event this month and has now amassed 11 straight match wins in Australia – equalling her tally for the whole of 2021.

“Wow, that’s gone well so far,” she said. “I am really proud of myself.”