In a fine final which never quite hit the stellar heights of their Roland-Garros thriller five weeks earlier, Sinner proved too icily consistent for the slightly under-par champion on a stiflingly warm afternoon on Centre Court on Sunday, prevailing 4-6 6-4 6-4 6-4 for his fourth grand slam title.
The 23-year-old world No.1 recovered from losing the first set, which Alcaraz wrapped up with the sensational shot of the match, to then largely control proceedings with the relentless ferocity and accuracy of his piercing groundstrokes to seal victory in four minutes over three hours.
That was nearly two-and-a-half hours longer than his agonising loss in Paris when he held three Championship points but couldn't convert, allowing Alcaraz to escape for a morale-crushing fifth straight win over him.
"This is the part I'm the proudest of because it really has not been easy," revealed the 23-year-old. "But I believe if you lose a grand slam final that way, it's much better like this than someone kills you.
"Then after you keep going, keep pushing. I did a lot of intensity in every practice because I felt like that I could play very good. That's why I also said after Roland Garros that it's not the time to put me down. No, because another grand slam is coming up -- and I did great here."
After collecting the trophy from Kate, Princess of Wales, Sinner told the crowd: "I'm just living my dream, it's amazing."
The first ever champion from Italy, he'd delivered a masterclass of control and composure after the disappointment of losing a fairly flat first set when Alcaraz suddenly came up with some familiar magic to conjure up the set-winning break.
Sinner thought he'd saved the set point when he powered what seemed an unstoppable forehand deep into the corner only for the Spaniard to stretch and produce an unfeasibly brilliant backhand winner.
But Alcaraz threw in a sloppy service game straight afterwards - something he'd been guilty of more than once during his fortnight's defence - as Sinner greedily grasped the chance to hit back.
There were moments of sublime brilliance from the pair but just as many mistakes, with Sinner hitting 40 winners and the same number of unforced errors while Alcaraz's tally was 38 and 36.
But the real champagne stuff came early in the second set when Sinner had to delay his serve at a critical moment when a cork flew out from the crowd and nearly hit him.
It prompted the memorable rebuke from British umpire Alison Hughes: "Ladies and gentlemen, please don't pop your champagne corks as the players are about to serve."
"Only here at Wimbledon," Sinner later observed dryly. "But that's exactly why we love playing here. It's a very expensive tournament!"
At 5-4 up in the set, Sinner delivered his own champagne game, chasing down an Alcaraz drop shot and cracking a forehand winner down the line to bring up set point before slapping another winner cross-court.
From there, Alcaraz always looked in trouble, and it felt unsurprising when the relentless Italian struck again at 4-4, another huge forehand earning him the key break.
Another one came at 2-1 in the fourth, but Alcaraz had no answers this time with his serve not functioning at its best as he suffered his first defeat in six grand slam finals.
"A little bit sad about losing, but with the head really high," sighed Alcaraz after the end of his 24-match winning streak.
Sinner's early season misery when he had to serve a doping ban seemed like ancient history as he added the Wimbledon crown to his Australian Open and US Open titles. If he had converted one of those match points at Roland Garros, he would now be holding all four titles.
And one final penny for the thoughts of Grigor Dimitrov, the Bulgarian veteran who was two sets up on Sinner in the fourth round before he suffered a match-ending injury while serving. It was the Italian's passport to victory.
