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#NextGenATP Greek Stefanos Tsitsipas reacts after defeating Roberto Bautista Agut to reach his maiden major semi-final.

Tsitsipas Outworks The Ironman To Make Aussie Open SF

Greek will meet Nadal in SF

It didn't have the flair or style of his victory against Roger Federer, but Stefanos Tsitsipas' win against Roberto Bautista Agut showed an entirely different – and maybe more impressive – side of the 20-year-old Greek. Where he wowed the Federer crowd with shake-your-head winners, against Bautista Agut, Tsitsipas showed the hustle and grit it might take for him to win his maiden Grand Slam title this fortnight.

The reigning Next Gen ATP Finals champion reached his first Grand Slam semi-final on Tuesday, ending the ironman run of Spain's Bautista Agut 7-5, 4-6, 6-4, 7-6(2) under the baking Melbourne sun.

Tsitsipas admitted even he is surprised by his form. “You have a bigger picture of your opponent when he's going to come out,” he said. “You think he's going to do some extraordinary things. But Roberto was playing great today. He showed some good tennis the entire week.

“What I realised recently, your opponent feels the exact same thing you feel. It's a pretty balanced match. The difference is who is going to press more and be more aggressive than the other. But I did surprise myself a little bit with my performance.”

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The Greek was slow to start his first quarter-final and fell behind a break in the first three sets, including a 2-4 deficit in the third. But he returned to his net-charging play that helped him knock out Federer and woke up his cadre of Greek fans, who had been quiet for much of the quarter-final, before controlling the fourth-set tie-break with more aggressive play.

Tsitsipas becomes the youngest man (20 years 168 days) to reach the Australian Open semi-finals since Andy Roddick (20 years 149 days) in 2003 and the youngest man to reach a Grand Slam semi-final since Novak Djokovic (20 years, 110 days) at the 2007 US Open.

Tsitsipas, who had reached only one fourth round at a Slam before this fortnight, set three main goals to start the year: Crack the Top 10 of the ATP Rankings, make the Nitto ATP Finals in November, and reach a Grand Slam semi-final. Three full weeks into the season, and he's a third of the way there. He will face 17-time Grand Slam champion Rafael Nadal.

“I'm just living the dream, living what I've been working hard for. I mean, I feel a bit emotional but not too much because I know, again, I really worked hard to get here, the semis of a Grand Slam,” Tsitsipas said.

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The Greek had to endure a nervy start inside Rod Laver Arena, dumping an overhead into the net to lose his opening service game. Bautista Agut somehow looked the fresher, despite having played three five-set matches out of four to make his first quarter-final.

The 30-year-old was moving Tsitsipas from tramline to tramline and landing passing shots at the 20-year-old's ankles when the Greek sprinted forward. But Tsitsipas began to probe Bautista Agut's legs, hitting behind the Spaniard again and again, and he broke in the 12th game to take the opener.

Another slow start in the second, however, doomed Tsitsipas' chances, as Bautista Agut never let up and Greece's #NextGenATP star lacked the precision that helped him knock off his idol on the same court two days earlier.

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A five-set match became a three-set match, and Tsitsipas honed in his focus, pounding Bautista Agut's backhand, making the Spaniard, who was finally showing the effects of his marathon run, stretch with both hands and stay home. Two, three, four consecutive topspin-heavy shots to the backhand, and Tsitsipas would then step in to rip a forehand down the line or race forward for a putaway.

Tsitsipas was playing very good. I had my chances in the first set and in the third set. I lost both sets... He played really good at the end of both sets,” Bautista Agut said.

The fourth set was a serving contest until the tie-break, when Tsitsipas, the fresher of the two, had just enough left to take the tie-break and book a spot in the final four.

He might land that Top 10 ATP Ranking he's chasing this fortnight as well. Tsitsipas is projected to climb to No. 12 and, if he makes the final, he's projected to enter the Top 10.