The 12th-seeded Fritz came through against the fourth-seeded 2020 runner-up 7-6(2), 3-6, 6-4, 7-6(3) and will face either American compatriot Frances Tiafoe or Grigor Dimitrov of Bulgaria for a place in Sunday's final.
Zverev's defeat means world number one Jannik Sinner is the only top-four player left in the draw following the shock early exits of Novak Djokovic and Carlos Alcaraz.
"I have had a few looks at Grand Slam quarter-finals over the years so I felt it was my turn to take a step further," said Fritz who cracked 12 aces amongst his 45 winners.
"I've always had a big serve but at the top of the game it comes back a lot more.
"So I've tried to add more to my game with drop shots, coming to the net to back up the serve."
On Tuesday, Fritz saw three set points come and go in the opener before sweeping through the tie-break.
Zverev registered the first break of the match in the eighth game of the second set on his way to levelling the quarter-final.
The two men exchanged early breaks in the third set until Zverev's serve let him down in the 10th game. Fritz got into the rallies and converted a fifth set point to go ahead in the tie for the second time.
Zverev saved two break points in the sixth game of the fourth set but once Fritz had won a lung-busting 24-shot rally in the tie-breaker, he had the momentum for victory.
