It took a brave call from the Newmarket handler not to let the three-year-old take on stablemate Enable in the Arc, but it proved the right one after he demolished a high-class field to provide his sire Frankel - who won the race in 2012 - with a first top-level success in Europe.
Plenty doubted whether the Anthony Oppenheimer-owned colt would have the necessary speed on his switch back to a mile and a quarter, having been campaigned over two furlongs further in his last four starts, and those that did were suitably silenced.
Having raced prominently throughout, and with his stamina assured, the 13/8 favourite readily drew clear once sent to the front by Dettori, entering the home straight to eventually cross the line seven lengths clear of Poet's Word with Highland Reel a neck back in third.
Cracksman, who completed a Group One double for Dettori and Gosden after they earlier captured the Queen Elizabeth II with Persuasive, was cut to 4/1 for next year's Arc by Sky Bet.
Gosden said: "He is a lovely horse and has improved through the year. I thought he ran a blinder at Epsom in the Derby, he was unlucky in Ireland, but boy, with Capri the form was good.
"He seems to have got bigger and stronger. If he started a middleweight, he is now a light heavyweight.
"He handled the ground better than anyone and he has won it in true style. Coming down Tattenham Corner (in the Derby) he got in a dreadful muddle, but he is learning. It is great for Frankel to have a son win the race he won.
"I think in the Arc it was a difficult decision, but I think Enable was more in the zone and streetwise than him. I was happy with the decision we made and I think it was the right decision."
Dettori he echoed the thoughts of Gosden in describing Cracksman as being much closer to the finished article now.
He said: "What I rode today is not what I rode at Epsom. He has developed and is stronger. He is a good horse now. I was surprised with the way he travelled as he can be a little bit laid-back in his races.
"He jumped and travelled and the pace was honest. I played my ace card where it was 'catch me if you can' because I knew he would get to the end no problem.
"It was a storming performance. I am thrilled for everyone. It was Frankel's first Group One in Europe and my first Champion Stakes. There were a lot of firsts and it was a great performance."
He added: "Today is Cracksman's day, let's enjoy him. If I had to choose between him and Enable I wouldn't know who to ride, they are two champions and we go into the winter to dream."
Gosden said: "I really hope Frankie does (have a difficult decision to make between Enable and Cracksman), we hope the horses have a good winter and go through to next year, but I've been around long enough not to count too many chickens."
While the victory did not come as a surprise to his owner, the manner in which it was achieved most certainly did.
Oppenheimer said: "It was amazing, especially as it was over a mile and a quarter. It was miles beyond what I expected. I thought it would be a tough race. It was amazing, he just took off. I am in quite a shock. He is a completely different horse now."
Poet's Word was backing up his second to Decorated Knight in the Irish Champion Stakes, and his trainer Sir Michael Stoute said: "He's run well. He's pretty versatile ground-wise and trip-wise, but I don't think he wants the ground as bad as this.
"I'm very pleased with him and he's been beaten by a very good one today."
Aidan O'Brien said of Highland Reel: "I'm very happy and he ran a great race. He'd like the ground quicker and he'll probably go to America (3/1 with Sky Bet for the Breeders' Cup Turf) next if everything is well."
