Alcaraz came under intense pressure throughout a spellbinding third-round contest played in a superb spirit and which had the crowd fully involved.
With his back to the wall when trailing by two sets to one and being outplayed by the swashbuckling Tiafoe, the Spanish third seed suddenly found an extra gear to seize control.
Tiafoe looked on the verge of avenging the five-set defeat he suffered against Alcaraz in the semi-finals of the 2022 US Open deep in the fourth set.
But Alcaraz responded in devastating fashion to blaze through the tiebreak and the fifth set was one-way traffic as Tiafoe's energy levels finally began to subside.
Alcaraz clinched victory with a drop shot and the two players embraced warmly at the net as the crowd erupted.
His victory means he has now reached at least the fourth round in 10 of his first 14 Grand Slam tournaments.
"It's a big challenge playing Frances and once again he showed he deserves to be fighting for big things," Alcaraz, who went on to win his first Grand Slam title having beaten Tiafoe at Flushing Meadows two years ago, said on court.
"It was really difficult to adapt my game and to find solutions to put him in trouble today. I had difficult moments in the fourth set but was thinking just fight one more ball."
Forty nine years ago to the day, Arthur Ashe had become the first Black man to win Wimbledon.
The way Tiafoe, born in Maryland to parents from Sierre Leone, played for most of the contest it did not seem fanciful to imagine him following in Ashe's footsteps.
With the roof closed, Tiafoe turned the power dial up to 11 - belting the ball to all corners of the court and displaying his trademark athleticism around the grass.
Alcaraz did lead 4-2 in the opener but Tiafoe broke back and then broke serve again at 5-5 with a hammered forehand pass before holding serve to clinch the set.
Three-time Grand Slam champion Alcaraz appeared to have built some momentum with a five-game roll that helped him level the match but Tiafoe had other ideas.
Attacking at every opportunity, Tiafoe broke serve at 3-3 in the third set and Alcaraz was wobbling as he was again forced to work hard at 3-5 to stay in the set.
Tiafoe duly held serve to move to within one set of the biggest win of his career and was knocking on the door throughout the fourth set with Alcaraz subdued.
At 4-4, 0-30 on the Alcaraz serve it seemed Tiafoe was closing in on a huge shock. It was the closest he came though.
When Alcaraz won a point he had no right to, clawing back a Tiafoe volley to lead 2-0 in the breaker, he raised his fist aloft to crowd and was suddenly re-energised as he took an epic tussle into a deciding set.
Whether a nasty slip near the baseline late in the breaker affected Tiafoe, only he knows, but his challenge faded fast after that and Alcaraz roared home.
