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Just as he did in his third-round victory against Frances Tiafoe, Fils reacted to mid-match physical struggles by upping the aggression in his game. After receiving treatment on his back at the end of the first set, he wore down World No. 2 Zverev with his powerful hitting for a two-hour triumph.

“I was feeling not great in the rallies. I’ve had a little problem in my back since I was young, so sometimes it hurts me a little bit," Fils said. "I had to find a rhythm, [be] more aggressive and come into the court to play my game and not let him play, because when you let him play he is one of the best tennis players in the world. 

"I’m really happy about the way I did it.”

Even after his free-hitting exploits had helped him clinch the second set, Fils soon found himself a break down at 1-3 in the decider. Yet he reeled off four straight games from there to take control of the match before serving out for a victory in which he struck 25 winners to Zverev’s 13. 

Fils, who also defeated Zverev to lift an ATP 500 title in the German’s hometown of Hamburg last July, converted three of five break points he earned inside Hard Rock Stadium.

“In the third set I thought it was over, at 1-3 and with him serving great,” he said. “I just said, ‘Okay, don’t get mad. Just try to play as much as you can and try to fight, and if you get a break, it’s nice’. It happened, so what can I say.”

Having also reached the quarter-finals at the BNP Paribas Open in Indian Wells earlier this month, Fils is only the third Frenchman to reach the last eight at both ‘Sunshine Double’ events in the same year after Yannick Noah (1896-87, 1989) and Gael Monfils (2016). He will take on Jakub Mensik in the quarter-finals.

Regardless of how that match goes, Fils is set to rise above his career high of No. 18 in the ATP Rankings after Miami. He is already up three spots to No. 15 in the ATP Live Rankings.