Stefanos Tsitsipas was proud to show his victory over Roger Federer was no accident as he continued his grand slam breakthrough by reaching the semi-finals of the Australian Open.

Backing up such moments is notoriously difficult but Tsitsipas bucked the trend by battling to a 7-5 4-6 6-4 7-6 (2) win over Spain’s Roberto Bautista Agut in three hours and 15 minutes.

The 20-year-old Greek had to dig deep on Rod Laver Arena, coming from a break down in the first and third sets before proving stronger in the fourth.

He fell to the court when Bautista Agut’s final return landed in the net and can look forward to a clash against either Rafael Nadal or Frances Tiafoe on Thursday.

Tsitsipas’ achievement makes him the youngest man to reach the last four at Melbourne Park since Andy Roddick in 2003 and the youngest at any slam since Novak Djokovic at the US Open in 2007.

He said: “It all feels like a fairytale almost. I’m just living the dream, living what I’ve been working for. I feel a bit emotional but not too much because I know I really worked hard to get here.”

The Greek told his team in the off-season that one of his goals for the year was to reach a slam semi-final.

“When I was answering this question I thought I was crazy but it is real and it just happened,” he said.

Tsitsipas was well aware of the possibility of a letdown after the Federer win, and added: “I had to stay focused, stay concentrated, and I’m really glad I played well today because I showed it didn’t happen accidentally.”

The 20-year-old admitted it was not easy to move on from one of the most talked about recent slam results.

“It was really tough,” he said. “The first night was tough to process. In the beginning it was tough to fall asleep. I had a pain in my toe, which kept me awake. In general, I felt a bit of pain in my body and tension.

“I slept less than six hours. I was worried about my next match, if I’m going to be able to get some good sleep the day before.

“I received a lot of messages, a lot of congratulations from people, from celebrities back home, which I never thought they were watching tennis. It kind of felt like the whole thing has a big impact in the country.

“I did want to concentrate on my next match. I knew that win against Federer was important, played a huge role in my image, who I am. But I knew that the biggest challenge was today’s match, that I can prove myself once again.”

Federer did not manage to break the Tsitsipas serve at all despite 12 chances during their match but the danger of a hangover was immediately apparent as it took Bautista Agut just one game.

However, Tsitsipas responded well, recovering the break and going on to take the set, a pattern he repeated in the third after Bautista Agut had levelled the match.

The 30-year-old Spaniard was finally starting to look weary, which was no surprise given his run through to the last eight.

He needed five sets to beat Andy Murray, John Millman and Marin Cilic, with only a third-round victory over Karen Khachanov being in any way straightforward.

He won a long rally with a forehand onto the line to save a match point at 5-6 in the fourth set, but Tsitsipas seized the initiative in the tie-break and did not look back.

Bautista Agut admitted his heavy schedule had caught up with him, saying: “I was a little bit tired or feeling the last matches I played here.

“But it’s my best result in a slam. I have to be happy about how I played during all the tournament.”