There were question marks about the colt's stamina, but Jim Bolger's 5-4 favourite was ultimately undone by the stop-start pedestrian early pace - described as "stupid" by another jockey, Jamie Spencer - and effectively carted his jockey Kevin Manning to the front on the descent to Tattenham Corner.
As a direct consequence of having expended far too much energy too early, Dawn Approach was one of the first horses beaten as they turned for home and he trailed in last.
If you are going to get beaten for the first time, you might as well do it properly. A line can now be put through this effort, although you can be sure he will never tackle the trip again. "This was not a good outcome," said Bolger, summing up his race.
"I was just a passenger," said Manning, who is one of the weighing room's strongest. "He got too competitive after 100 yards. He ran too free and I knew it was impossible for a horse to pull that hard and win the Derby."
In contrast, Moore was all smiles. The jockey has proven himself time and time again as a safe pair of hands on the big occasion and again he made no mistake.
"It's the most important race of the year and I was lucky enough to be riding the best horse in it.
"He did an exceptional job for me. We did go very slow and the field was very tight. I was getting caught wide without cover early on, so I had to drop him in a bit further back than I wanted, but I got a nice clear run. He got to the front quickly and then it was a matter of toughing it out."
O'Brien, who ran five in the race, also saddled the fourth home, Battle of Marengo, ridden by his son, Joseph.
"We are lucky to be in the position we are in, to get such good horses. They are incredibly well-bred horses and, even before they are mated, the dream is for this to happen," said O'Brien after the event. " We thought coming into the race he was a solid horse but he's still a baby.
"The whole thoroughbred breed hinges on the Derby, it's what racing's about for everyone working in stables and on studs. I'm sure the lads will have a celebration tonight, but it's back to work in the morning."
There was almost as big a crowd around the runner-up Libertarian after the race. The colt passed four horses in the last 100 yards to secure second for Elaine and Karl Burke.
"The pace didn't help and there was 100 yards around Tattenham Corner where he lost his way a bit and that probably cost him the race, but he's lived up to our expectations - and more," said Karl Burke.
"If you'd seen him, a big raw, unraced 3-year-old in January, you'd never have imagined we'd be here."
Theirs would have been the fairytale result but, for O'Brien, Coolmore and Moore, this year's Investec Derby was more a case of business, big business, as usual.Telegraph Group Ltd
