Thomas Chippendale (9-2) relegated stablemate Noble Mission (4-1) to second at Royal Ascot in the King Edward VII Stakes.
Sir Henry Cecil was winning this Group Two contest for the eighth time in his distinguished career (and a 75th winner at Royal Ascot) although it was his stable's second string that prevailed.
Carrying the colours of Sir Robert Ogden, Thomas Chippendale stepped out of handicap company to prevent Frankel's full brother from emulating his illustrious sibling.
Investec Derby third, and odds-on favourite, Astrology took the field along at a sensible pace in the soft ground but looked in trouble from the moment Epsom fourth Thought Worthy moved alongside on the home turn.
William Buick's mount eased past his labouring rival but edged left under a right hand drive inside the distance, hampering Noble Mission.
Johnny Murtagh was on the outside of the pair and less inconvenienced by the barging but his mount looked good value for his victory regardless of the trouble as he stayed on strongly to record a half length success.
Murtagh said: "Noble Mission came there, but my lad was just getting organised - he's still a little bit green and a little bit raw.
"When I put my stick down and changed my hands he accelerated again to the line and won going away.
"He's a bit of a baby and he's still learning. It's an honour to ride for such a wonderful trainer as Mr Cecil and to ride a Royal Ascot winner for him is great."
Cecil said: "I'm delighted for Sir Robert (Ogden, owner) and he's an improving horse.
"He looks as if he stays well and he could even be a St Leger horse.
"I thought both horses deserved to run as they both had a chance.
"The Derby third (Astrology) is a good horse but I thought he had a hard race in the Derby.
"My horses are owned by two different owners and I hate one beating the other, but they both ran very well. Noble Mission has run a very good race and he's improving as well."
John Gosden said of the third home, Epsom Derby fourth Thought Worthy: "He ran a great race and he was just done for a bit of toe.
"We'll give him a bit of a break and he'll have one more race before the Leger.
"We can pick and choose which one."
Aidan O'Brien felt that Astrology may still have been feeling the effects of his run earlier in the month at Epsom.
He said: "Maybe Ascot came a bit quick, I don't know. He seems to be fine."
Ryan Moore reported that the favourite, who beat just one rival home, was never travelling and that his colt didn't handle the sticky ground.