Jessica Harrington's charge was sent off the 11-8 favourite for the Group Two affair despite being edged out in the Futurity Stakes and settled on the outside by Shane Foley, tracking the pace set by Van Gogh.
Cadillac travelled well throughout the mile heat, and when Foley asked his partner to quicken inside the final furlong, the Lope De Vega colt displayed an electric turn of foot, quickly pulling clear to run out a three-and-a-half-length winner over Van Gogh. Reve De Vol was a further two and three-quarter lengths back in third.
Coral made Cadillac their 8-1 co-favourite for next year's 2000 Guineas, with Betfair cutting him from 33-1 to 12-1 for the Newmarket Classic.
The latter also go 5-1 about his chances for the Breeders' Cup Juvenile Turf in the autumn and the trainer's daughter, Kate, indicated America could be the next port of call.
She said: "You'd have to be delighted with him. You saw the real Cadillac there today and he's a lovely horse.
"He's a horse that just goes through the motions at home, you don't really know how big an engine is in there, but it's fairly big.
"He didn't really learn much the first day, but learned a lot the last day and he did it right there today.
"It's great for the syndicate (Alpha Racing 2020), which we started two years ago and this is the second running of it. We're going to go forward with it next year and it's great to have a high-profile horse like this.
"I'd say all being well his next start will probably be in the Breeders' Cup Juvenile Turf."
Monday (12-1) made every yard of the running to claim the Ballylinch Stud Irish EBF Ingabelle Stakes.
Fourth on her only previous run, Seamie Heffernan had his Aidan O'Brien-trained mount sharply away, with better-fancied stablemate and 9-4 favourite More Beautiful settled on her heels.
However, Ryan Moore was pushing the market leader from some way out and it was left to No Speak Alexander to throw down a challenge, but she fell short by three-quarters of a length at the line.
The winner was introduced as a 33-1 shot for next year's 1000 Guineas by Betfair, and 25-1 by RaceBets, and she could now take a jump up in company.
O'Brien said: "She's the first foal out of Ballydoyle. She can step into a Group race fairly quick, I'd say.
"She probably learned a lot the first day and learned a good bit more today. I'd say she won't have any problem stepping up quick.
"The Boussac, Fillies' Mile, all those races will be open to her."
Tiger Moth (5-6 favourite) then made it a treble on the day for O'Brien with a clear-cut victory in the Paddy Power 'Is It 2021 Yet?' Stakes.
O'Brien also struck gold in the feature Irish Champion Stakes with Magical, and Irish Derby second Tiger Moth brought up the hat-trick with the minimum of fuss, coasting home by four lengths under Ryan Moore.
O'Brien said: "He's a lovely horse. Obviously his last run was in the Irish Derby.
"We gave him a break, said we'd come back here and maybe have a look at the Melbourne Cup, but he probably won't get in where he is. He's 8lb below Santiago.
"I wasn't sure a mile and a half was his thing and we would have been very happy going back to a mile and a quarter. It was a strong-run mile and a half and we were going to find out today whether he stayed or not."
Safe Voyage and Sinawann produced a fantastic finish to the Clipper Logistics Boomerang Mile, with John Quinn's British raider just grabbing the verdict in a photo.
Colin Keane, who had earlier struck Group One gold with Champers Elysees in the Matron Stakes, had to be at his strongest to get Safe Voyage (4-1) back in front on the line, triumphing by a short head.
He said: "I thought Ronny (Ronan Whelan, Sinawann's rider) was just after nabbing me, but to be fair to my horse, when the other horse came to him he put his head down and tried very hard.
"He travelled very strong, quickened well and when he did get by him, my lad fought back very bravely.
"He's been a revelation from winning the premier handicap in Galway to these Group Twos. It's a brilliant training performance."
Halimi (18-1) swooped inside the final furlong of the Irish Stallion Farms EBF 'Petingo' Handicap to collar the gutsy Springbank and repel the late thrust of Shoshone Warrior for Jim Bolger and Kevin Manning.
"I just spoke to the boss and he's delighted with the horse. He's a nice progressive type," said Bolger's daughter, Una Manning.
"We're thrilled with him and he'll go for more of the same. It's nice to win a big pot like this on Champions Day."
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