Any fears that Zverev might struggle after he jarred his left knee following an awkward fall in the previous round were quickly dispelled and such was his command of the contest, it seemed that nothing could stop him from finally reaching the last eight of the grasscourt major for the first time.
For two-and-a-half sets on Monday, Zverev's serve was impenetrable, just like it had been during the first week of the championships, as he notched up 56 successive holds over the course of four matches.
Zverev looked well set to defeat a top 20 player at Wimbledon for the first time as he led by two-sets-to-love and was locked at 4-4 in the third.
But a tame double fault from Zverev handed Fritz an unexpected break in the next game and from then on the American's game caught fire.
He chased down everything the German could throw at him and produced some eye-popping diving winners in the fifth set to leave a shell-shocked Zverev staring at defeat.
Facing two more break points at 2-1 down, Zverev stayed alive in the game by ending a brutal, yet captivating, 21-shot exchange with a ferocious forehand winner.
But across the net, he would also have seen that Fritz was prepared to put everything, including his 6-foot-4 body, on the line in an attempt to get over that finishing line.
Waving his outstretched racket arm, the American went flying to the ground as he desperately tried to get that Zverev forehand back over the net.
The disappointment of that missed attempt did not last long as Fritz secured the break on the next point for a 3-1 lead and from then on there was no way back for Zverev.
A backhand winner into an open court left Fritz dropping his racket and raising his arms in triumph, while Zverev was left to digest yet another disappointing exit from Wimbledon.
"It was amazing to do that on Centre Court when you are two sets down in front of this crowd. It's a dream," Fritz told the crowd after defeating a top-five player at a Grand Slam for the first time in his career.
"I was just thinking it sucked to be playing this well and to lose in three straights. Even though I lost the first two sets, I really believed I was playing good tennis.
"I felt it was just a couple of points here and there and that I could take it one step at a time and turn it around," added the 13th seed, who will next face Italian Lorenzo Musetti.
With Tommy Paul also through to the last eight, Fritz's victory means it will be the first time since 2000 that more than one American man will feature in the Wimbledon quarter-finals.
Despite fighting toe-to-toe with Fritz for three-and-a-half hours, during which Zverev regularly bombarded his opponent with 130 mph serves, fired down 19 thunderbolt aces and produced 55 winners, the German revealed he had been playing on "one leg."
"It was fairly obvious that I wasn't 100% today, right?" Zverev asked reporters before elaborating that an MRI scan had shown that he had a tear in his knee capsule as well as bone bruising.
"I wasn't moving really the entire match. If I was running for a drop shot, I was limping there more than running.
"There weren't really long rallies because I couldn't play long rallies.
"Credit to him that he came back but it wasn't a great tennis match."