Trainer Sir Michael Stoute sent out this season's Eclipse winner Ulysses to win the mile and a half race 12 months ago and Crystal Ocean arguably came of age in this season's renewal.
A market mover for the Derby before he finished third in the Dante Stakes at York, he proved slightly disappointing at Royal Ascot when behind the re-opposing Khalidi.
That rival tracked Crystal Ocean while Mount Moriah and Jake's Hill cut out the early pace and the order barely changed although the field did close up with about six furlongs to run.
Mount Moriah led the field off the inside rail as they quickened down the hill and Ryan Moore opted to challenge up the leaders inside aboard Crystal Ocean. In contrast, Khalidi slipped round the other side but his mount was left trailing in the wake of his rival as Crystal Ocean quickened impressively.
Moore allowed the eventual winner to drift towards the far rail but it didn't prevent the Sea The Stars colt from quickening and he was good value for his three and a half length winning margin.
Sky Bet cut the winner to 6/1 (from 14s) for the William Hill St Leger.
Spokesman Michael Shinners said: "Sir Michael Stoute has already eschewed the option to contest one Classic in bypassing the Derby with Crystal Ocean but if he does head to Doncaster with this progressive son of Sea The Stars, then Crystal Ocean would look to have all the right credentials to run a big race on Town Moor and he's now 6/1 with ourselves for the St Leger."
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Moore, however, was quick to pour cold water on talk of a potential Classic bid, saying: "He'll stay, but I don't really think he's a mile and six horse.
"He's got plenty of ability and he will get better next year, I don't know if he's a Leger horse. That will be for Michael to decide, he's got a couple of months to get there yet. He's a lightly-raced colt and he's progressed with every run. He'll be better as the year goes on and be better next year."
Stoute, who was winning the race for a tenth time, seemed much keener on a Leger bid.
He said: "He is a horse we've always liked and Ryan has always liked him to. We knew he handled soft ground as he did in the Dante. My only concern was would he handle this ground. He is very adaptable.
"We are certainly thinking about the St Leger. We will see how he comes through this. I said before the Dante we didn't consider him as a Derby horse as he had got to be more mature going into Epsom. He is pretty good at this trip. We may do a Conduit (did the Gordon-Leger double in 2008) and have a one of fling (at a mile and thrree-quarters)."
Thady Gosden, pupil assistant to his father, John, said of the runner-up Khalidi: "Frankie (Dettori) said he ran very well but he didn't handle the ground. It was a little bit too soft for him.
"The plan now is to freshen him up and hopefully take him to the St Leger, all being well."
Khalidi is a 20/1 chance for the Doncaster Classic with stablemate Stradivarius 9/2 second favourite with Sky Bet.
Frankie Dettori, who rode the son of High Chaparral, will be hoping for better conditions in September, adding: "He didn't handle the ground."
Ralph Beckett, trainer of the third home Mount Moriah, commented on his Mount Nelson gelding's performance: "He has run very well, but he wants further.
"He is a half-bother to a Dark Angel horse who gets a mile and a half! This is on the sharp side for him. He has run very creditably. The two ahead of him in the market had to really underperform for him to have had a chance of winning. They didn't, so he didn't."
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