The Betfair Cup went to Godolphin's second string Byron under Kerrin McEvoy at Goodwood this afternoon.
Naahy adopted his customary front-running position, but succumbed to his rivals in the closing stages as Byron swept into the lead in the final furlong.
The 16-1 shot quickened away, while Suggestive finished well to get to within three-quarters of a length in second.
Dettori could never strike a blow and had to settle for third aboard Godolphin's principal hope Kheleyf (9-4 favourite), a further three-quarters of a length behind.
Earlier, Maraahel overturned the odds on hot favourite Duke of Venice to land the ABN Amro Stakes.
Sir Michael Stoute's Alzao colt struck the front two out and refused to give way to run out a winner of the recognised St Leger trial at 9-4.
As the Godolphin favourite dropped out tamely, Go For Gold ran on to snatch second at 25-1 with the lightly-raced Remaadd at 5-1.
Tournedos came with a super late run to snatch the Betfair Molecomb Stakes right on the line. Mary Read looked sure to prevail after skipping clear of the field at the furlong pole.
But jockey Ted Durcan switched the Rossini colt to the outside and he simply flew home at 14-1 to win by half a length.
The 25-1 shot Mary Read was a shade unfortunate to be caught within yards of the line and the 66-1 early leader Safari Sunset completed a festival for the bookies by staying on for third.
Coat of Honour stayed on gamely to win a competitive Sterling Insurance Summer Stakes.
Sir Mark Prescott's four-year-old put his disappointment in the John Smith's Cup well behind him by running out a neck winner at 10-1 despite swerving around in the closing stages.
The fast-finishing Impeller had to settle for second at 9-1 while Bonecrusher, last early on, flew late for third at 25-1.
The 9-2 avourite Fantastic Love flattered early in the straight but faded in the final quarter-mile.