Greek rising star Stefanos Tsitsipas was living the dream Tuesday after powering into the Australian Open semi-finals where he was joined by fellow giant-killer and Grand Slam last four debutant Danielle Collins.

The 20-year-old, who ended Swiss great Roger Federer’s tournament, reinforced his new-found status with a measured 7-5, 4-6, 6-4, 7-6 (7/2) win over Spain’s Roberto Bautista Agut on Rod Laver Arena that left him emotional.

In doing so, the 14th seed became the youngest man to reach the semis at Melbourne Park since Andy Roddick in 2003 and the first player from Greece – man or woman – to get so far at Grand Slam.

Unseeded American Collins, the world no 35, had never won a Grand Slam match before entering this year’s tournament but she stunned three-time major champion and second seed Angelique Kerber in round four.

And the 25-year-old from Florida continued her fairytale run by bouncing back spectacularly to down Russia’s Anastasia Pavlyuchenkova 2-6, 7-5, 6-1 in the quarter-finals.

Tsitsipas’s exploits line him up with semi-final against either fellow young gun Frances Tiafoe of the United States or 17-time Grand Slam-winning Spaniard Rafael Nadal.

“I’m just living the dream, living what I’ve been working hard for,” said Tsitsipas, who lives in Cyprus but trains at the academy of Serena Williams’ coach Patrick Mouratoglou in France.

“I feel a bit emotional but not too much – I know I really worked hard to get here, playing in semis of a Grand Slam.”

Bautista Agut, seeded 22, acknowledged Tsitsipas was playing well, but with Nadal and Novak Djokovic still in the tournament he doesn’t give him much chance of winning the title.

“Of course, he has a lot of time to improve, a lot of time to get enough experience to be in the finals of these tournaments,” he said. “But here I think Rafa and Novak are my favourites.”

It will be fun

Collins, who has spent long stretches of her career playing small tournaments to build up her ranking points, was in big trouble after losing the first set to world no 44 Pavlyuchenkova. But she fearlessly battled back into the match to again stamp her mark on the tournament.

“Yeah it’s my first time to play on Rod Laver, I didn’t even practise on here. It was quite the experience. I really love it,” said the ecstatic Collins, whose reward is a semi-final against Petra Kvitova.

Nadal, meanwhile, looks to move another step closer to winning an event he has only claimed once before among his 17 major titles against Tiafoe, who announced himself on the world stage by beating fifth seed Kevin Anderson in the second round.

The Spaniard, who has been in ominous touch so far, is wary of the threat posed by the 21-year-old, who has nothing to lose. “He has everything. He’s quick. He serves well. Very quick forehand,” said the second seed, who has not dropped a set so far. He’s a very dynamic player, aggressive one. Of course, he’s dangerous.”