(CNN) - Stefanos Tsitsipas confirmed his status as one of the brightest hopes in tennis two days ago, upsetting Roger Federer, before becoming the youngest man to reach the Australian Open semifinals in 16 years with a bruising, three-hour quarterfinal win Tuesday.
He is not a bad salesman, either.
After defeating a brave Roberto Bautista Agut 7-5 4-6 6-4 7-6 (7-2) in a battle of maiden grand slam quarterfinalists, the Greek phenom urged a captive Rod Laver Arena to give his YouTube channel some love.
"If you haven't subscribed, please subscribe," Tsitsipas, who chronicles his travels around the world on the channel, told spectators Tuesday.
They will probably do anything he wants, such is the charisma of the 6-foot-4 Greek and their affection in turn for the fast-rising 20-year-old, currently ranked No. 15 in the world.
Indeed, just after his interview, his subscriber tally climbed from around 23,000 to 29,000.
But while one crowd favorite progressed, an even bigger one in Australia fell short as Queenslander Ashleigh Barty lost to a sterling Petra Kvitova 6-1 6-4. It means the host nation will have to wait at least another year to produce a home winner for the first time since Chris O'Neil in 1978.
Kvitova, though, has always been liked herself and the Czech winning the title would be some tale given the double Wimbledon champion was lucky to be alive after being attacked in her home in 2016.
"I didn't ever imagine being back on this great stadium and playing with the best," an emotional Kvitova said. "It's great."
American Danielle Collins, who joined Tsitsipas as a first-time slam semifinalist, plays Kvitova Thursday for a place in the final. Collins extended Kvitova to three hours in Brisbane the first week of the season.
The fiery world No. 35 -- a loser in all five of her grand slam encounters entering Melbourne -- came back to beat Russia's Anastasia Pavlyuchenkova 2-6 7-5 6-1.
She continues the streak of unseeded women's semifinalists in Melbourne stretching back to 2015.
Tsitsipas' flashy game and ability to orchestrate the Melbourne crowd mirror one of his closest friends on tour, Marcos Baghdatis, during his improbable run to the Australian Open final in 2006. He was finally stopped by Federer.
Then, the Cypriot received ample, vocal support -- and Melbourne's large Greek community have been out to cheer on Tsitsipas, too.
Even Federer took note of the audience's energy, following his stunning four-set loss, when the Swiss went an incredible 0-for-12 on break chances.
"I loved the crowd," said Federer. "I think they were fantastic."
Tsitsipas said his perspective on life changed when he almost drowned while swimming in the sea as a teenager and had to be rescued by his dad.
So when Tsitsipas also used the term "fairytale" to describe what has transpired in Melbourne, one can understand why.
Bautista Agut will never match Tsitsipas -- who hit 22 aces along the way to defeating his Spanish opponent -- in charisma or flamboyance, but the crowd warmed to the workmanlike 22nd seed too, due to his sheer determination.
Despite his obvious fatigue -- the Spaniard contested three five-setters, knocking out grand slam winners Andy Murray and Marin Cilic, and local favorite John Millman -- he pushed Tsitsipas to the limit.
"Today I was a little bit tired or feeling the last matches I played here," said Bautista Agut, who downed world No. 1 Novak Djokovic en route to the title in Doha early this month.
Bautista Agut led 4-2 in the first three sets, only to lose two of them.
Yet the 30-year-old gutsily forced a tiebreak in the fourth after saving a match point at 5-6 with a stunning forehand winner.
Tsitsipas grabbed a 4-2 advantage in the tiebreak and won the seventh point after he raced around the court to hit a defensive lob.
A deflated Bautista Agut couldn't rally again.
No issue for Federer
The Swiss legend also praised Tsitsipas for his play and commitment to tennis -- and the 20-time grand slam winner chooses his words carefully.
Tsitsipas became the second player in succession to win the Next Gen finals -- an ATP competition for players 21 or under -- and then advance to the semifinals at the Australian Open several months later.
He followed in the footsteps of the now injury-hit Hyeon Chung, who hails from South Korea, another country not known for producing an overflow of tennis pros.
Tsitsipas has already achieved his goal of making a grand slam semifinal in 2019 -- with his power, ability to cover the court and variety in his game, managing it at the first attempt.
This, while his fellow 'Next Gen' star and rival Alexander Zverev continues to struggle at the grand slams.
"I'm just living the dream, living what I've been working hard for," said Tsitsipas.
Most of his family have been along for the ride, including his tennis-inclined parents, brother Petros and younger sister Elisavet.
"She's the mascot," said Tsitsipas.
Stern test approaching
Tsitsipas will face the winner of Tuesday's other quarterfinal -- either 17-time grand slam champ Rafael Nadal or his fellow 'Next Gen' star Frances Tiafoe -- in the semifinals.
But can Tsitsipas win the whole thing?
Not according to Bautista Agut.
"Here I think Rafa (Nadal) and Novak (Djokovic) are my favorites," he said.
Sounds about right -- but Tsitsipas could be joining the duo as a grand slam winner sooner rather than later.
The-CNN-Wire ™ & © 2019 Cable News Network, Inc., a Time Warner Company. All rights reserved.