Richard Hannon junior has warned any potential rivals that he feels Canford Cliffs is still improving ahead of next month's Queen Elizabeth II Stakes at Ascot.
Since finishing third in the 2000 Guineas at Newmarket, the three-year-old has won three times in Group One company, most recently outpointing Rip Van Winkle in the Sussex Stakes at Goodwood.
Hannon junior, son and assistant to his father, said: "He travels well but what has turned him from a good horse into a great horse is that he's learnt to settle.
"I think he only got beaten in the Guineas because he pulled too hard too early and I really do think he is getting better.
"He's staying in training next year and he should go on from strength to strength.
"He's a very hard horse to beat and he's exceptional, we haven't had another one like him."
A trip to the Breeders' Cup at the end of the campaign would look unlikely for Canford Cliffs at this stage, but Hannon junior is putting any talk of an American jaunt on the back-burner until after Ascot.
"The main aim for him right now is the QEII so we'll go there and talk after that," he said.
Hannon also had news of another top-class miler in the yard, Dick Turpin, who is reported to be well following his disappointing display in the Juddmonte International at York.
The English and French Guineas runner-up was beaten a long way from home on the Knavesmire on his first try at a mile and quarter, although the Marlborough team are keen to rule out stamina issues being the reason for his eclipse.
"He's having a little break at the moment," Hannon said.
"The race at York didn't go our way and he was beaten a long time before stamina came into question.
"He got messed about a bit during the race and it wasn't very nice to watch but he's come out of it in one piece, is in good nick and we'll aim for some nice autumn races now at the back end of the year."