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Griekspoor served for the match at 5-4 in the second set before Zverev, who is bidding to equal a record three Munich titles, dug deep to claim a comeback win.

“I’m extremely happy. Finally, I won a close one,” Zverev said.

“I’ve lost a few of those in the past few months and I always said, ‘I need to get one of these’. I did today. I’m extremely happy with how I hung in there, especially in the third set, being 0/40 down in my second service game. I’m proud to win this match and looking forward to the next two, hopefully.”

Zverev bettered his head-to-head lead against the Dutchman to 7-2.

“Me and Tallon, we kind of always have weird matches,” Zverev said.

“In Indian Wells I was serving for the match and lost my serve, then he was serving for the match and lost his serve. So you never know with us two. It’s always entertaining, we always go the distance, and I’m happy with the win.”

Zverev will next take on Fabian Marozsan, who defeated Zizou Bergs 6-3 7-6 (7-4) in their quarter-final.

No.2 seed Ben Shelton and No.5 seed Francisco Cerundolo also made it through to the last four, wasting little time in their matches.

Shelton eased past Luciano Darderi 6-4 6-3 in 74 minutes to become the first American to reach a semi-final at a clay ATP 500 since the series was introduced in 2009.

Cerundolo required just one minute longer to beat David Goffin 6-2 6-4.

He will now seek to avenge defeat to Shelton in the pair’s only previous meeting at Indian Wells last year.