Alexander Zverev keeps his cool to see off rising star Learner Tien

Learner Tien showcased what makes him such an exciting talent in his first grand slam quarter-final before falling to Alexander Zverev at the Australian Open.

The 20-year-old American was bidding to become the youngest man to reach the last four in Melbourne for 34 years, but instead it was third seed Zverev who moved through to a 10th slam semi-final after a 6-3 6-7 (5) 6-1 7-6 (3) victory.

“Learner from the baseline was playing unbelievable,” said an impressed Zverev. “I don’t think I’ve played anyone who plays that well from the baseline for a very long time.

“I don’t know what Michael Chang has done with him in the off-season, but it’s incredible. Without my 20 something aces, I probably would not have won today.”

Tien’s rise is rapid and accelerating and his crowd-pleasing game was a big hit with the crowd on Rod Laver Arena, who could enjoy the cool air conditioning after the roof was closed because of extreme heat.

The cut-off mark of five on the tournament’s heat stress scale was reached just before the players walked onto court, meaning the whole contest was played indoors.

That would have been welcome news for the players, too, with temperatures pushing into the mid 40s outside.

Zverev had the edge in the opening set but Tien, who is coached by former French Open champion Chang, hung with the German in the second.

Tien lacks the raw power of his opponent or the German’s potent serve, which ultimately made the difference, but he already has a tremendous feel for the geometry of the court, while his hand skills on drop shots and at the net repeatedly caught Zverev out.

He trailed 5-3 in the tie-break but a tight forehand from Zverev levelled matters and Tien then played arguably his two best points of the match, sending an overhead from the third seed flying back past him before flashing an angled forehand winner

What Tien lacks is experience, and he was unable to maintain his intensity in the third set, while Zverev saved a set point with a big serve at 5-6 in the fourth before dominating the tie-break.

The 28-year-old is through to the semi-finals here for the fourth time, the most by a German man, and he is now one win away from matching last year’s run to a third grand slam final.