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Stefanos Tsitsipas, Andrey Rublev, Alex de Minaur and Jaume Munar will aim to reach the Next Gen ATP Finals championship match on Friday.

Tsitsipas, De Minaur Headline Semi-final Friday

Greek, Australian both unbeaten in round-robin play

After a thrilling final day of round-robin action at the Fiera Milano, four men remain at the Next Gen ATP Finals with ambitions of capturing the trophy.

Stefanos Tsitsipas and Andrey Rublev will meet for the first time at tour-level on Friday, in a repeat of a blockbuster first-round encounter on the ATP Challenger Tour last season. With both players yet to enter the Top 100 of the ATP Rankings for the first time, Rublev battled past Tsitsipas 6-2, 3-6, 7-6(7) in Quimper. But a lot has changed, for both men, since that meeting in France.

Top seed Tsitsipas arrives into the semi-finals with a 3-0 unbeaten record in Milan, dropping just one set in round-robin play to Jaume Munar. After a breakthrough season on the ATP World Tour, which included capturing his first title at the Intrum Stockholm Open, the World No. 15 will be looking to cap his stellar season by capturing the title at the Fiera Milano in Milan.

"[Andrey] won't give me that many opportunities like Hubert [Hurkacz] today," said Tsitsipas. "It's going to be a fight. It's going to be tough match to deal with.

"I'm going to have to be ready for that, for the battle. I'm going to have to be ready mentally to work hard to get that win."

As the only returning player from the inaugural Next Gen ATP Finals 12 months ago, 2017 runner-up Rublev will be eager to make his way back to the championship match after falling to Hyeon Chung last year. The Moscow native qualified for the semi-finals with a 2-1 record, defeating Taylor Fritz and Liam Caruana in his first and final group stage matches.

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In the first semi-final, Alex de Minaur will meet Spaniard Jaume Munar for a place in Saturday's final. Like Tsitsipas and Rublev, the pair has previously met below tour-level. On both occasions, Munar defeated the Australian in straight sets to win trophies in Spain. But De Minaur will be confident of notching his first win against the Mallorcan after an impressive Group B performance.

De Minaur dropped one set in three matches to emerge as the winner of Group B, beating Rublev, Fritz and Caruana to book his place in the last four. The 19-year-old, who reached tour-level finals in Sydney and Washington, D.C, this year, will be aiming to maintain his high level of performance as he bids to reach another championship match in 2018.

"Going into each day you've got different tactics. And tomorrow will be different," said De Minaur. "But I just want to go out there and keep doing what I've been doing. I've been serving well. I've been playing confident and just leaving it all out there."

Munar's chances of reaching the last four appeared bleak after losing his opening two matches in Milan, but an impressive three-set victory over Frances Tiafoe, coupled with Tsitsipas' victory over Hubert Hurkacz, earned the Spaniard a shot at reaching the championship match. After two victories below tour-level against his semi-final opponent, will Munar be able to maintain his winning record against De Minaur on such a big stage? That remains to be seen.