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The third seed overcame the Italian 7-5, 6-7, 7-5 after a thrilling two-hour, 44-minute quarter-final, during which Fritz was on the verge of a straight-sets victory with a 6/3 lead in the second-set tie-break. 

The American earlier held two consecutive match points on return at 6-5, including one he squandered by missing a backhand down-the-line return by centimetres.

“It was tough. I kept trying to tell myself that he played well and it’s not as much on me, so try not to get frustrated," Fritz said. "I think my best looks there I had three match points seeing a second serve from him. I think I really have to win one of those.

"I can’t be too frustrated with the 6/5 point, I honestly hit a really, really good serve and he full-commit leaned there. If I would’ve gone 110 mph wide, I probably would’ve aced him. He committed hard for the return and he crushed it. I got to give it to him, he raised his level a lot.”

As Berrettini forced a decider, Fritz remained composed, showing only positive emotions to regain his focus. The 28 year-old Berrettini, No. 26 in the ATP Live Rankings, applied consistent pressure on the American throughout the night.

After the first set, neither player surrendered serve until Fritz secured a pivotal break at 5-5 in the deciding set. Facing two break points at 5-5, 15/40 in the third set, Berrettini fired two massive first serves to stay alive. But on Fritz’s fourth break point of the set, the American seized the opportunity on Berrettini’s second serve. That was a key factor in the match, as Fritz won 62 per cent of his second-serve return points.

“There’s two options. Get frustrated, lose, and then be even more frustrated about all the chances I blew, or regroup and get the win,” Fritz said. “Now I can sleep tonight and not be so mad at the chances I blew.”

Improving to 5-0 against Berrettini, Fritz never wavered from his bold return strategy against the hefty server. 

“I feel like that’s how I’ve always returned his serve. I feel like he’s got such a big serve anyways, it’s pretty tough to take a full swing and hit it, even when you stand back. That also gives him time to run around and find the forehand,” Fritz said. “I’ve always liked to stand in, look to chip those forehands and hopefully it gets on him quickly, especially when I get a hold of a backhand, I feel like I can really crush it.”

Fritz is into his sixth ATP Masters 1000 semi-final and first in Miami. Up next for the eight-time tour-level titlist is Czech Jakub Mensik, who will be competing in his maiden ATP Masters 1000 semi-final.