Sportinglife Report:
Black Bear Island (12-1) came with a rare rattle to pip stablemate Freemantle and give Aidan O'Brien a one-two in the totesport.com Dante Stakes.
Johnny Murtagh tried to make all on Freemantle and a furlong out looked to have stolen the Derby trial.
However, Colm O'Donoghue, apparently on the second-string, absolutely flew home to claim the spoils, with Sans Frontieres also making eyecatching headway late to claim third.
After a week in which O'Brien had won Derby trials with Golden Sword, Age Of Aquarius and Fame And Glory, both his runners on the Knavesmire surprisingly drifted in the betting.
Murtagh had ridden Black Bear Island on his last start in France and warned punters he would improve a great deal.
However, it was Murtagh's mount Freemantle who made them all go, stretching the field out from some way.
Kite Wood had every chance if good enough while 2-1 favourite Crowded House failed to pick up.
But Black Bear Island sprouted wings in the final furlong and High Chaparral's full-brother got up to win by a head.
Victor Chandler reacted by cutting the winner to 10-1 from 20-1 for the Investec Derby, and the runner-up to 12-1 (also from 20s).
O'Donoghue said: "There was plenty of pace on through the race and he travelled really well.
"He really started to get going when I asked him in the final two furlongs and he picked up really well to lead on the line.
"Aidan told me to get him to switch off and relax and to let him enjoy himself through the race.
"What happens next will be up to Aidan, Mr Tabor, Mr Smith and Mr Magnier but I am just happy to have been riding him on the day."
Murtagh said of Freemantle: "He's run a great race, he just got tired in the last 100 yards, the ground was perfect for him."
While all Jamie Spencer had to say about Crowded House was: "He just didn't fire on the day."
Trainer Brian Meehan added: "There was always a chance he might need the run, but possibly he needed it a little bit more than I thought. Jamie said he felt flat and didn't pick up how he can.
"As far as I'm concerned he's still going for the Derby, but we will have to take him back and see how he is."
Barry Simpson, racing manager to Sir Robert Ogden, was thrilled with the third, Sans Frontieres.
He said: "That was a very pleasing run, it was nice to see him really stay on.
"He is still green and immature but I don't know yet what we will do with him now."
Michael Hills felt Redwood ran very flat, saying: "He didn't give me the same feel as he did at Newmarket, I just can't explain it, he was not nearly half the horse.
William Hill now have Irish-trained runners in the front six positions of their Derby betting, and go 1-6 about an Irish winner with 1-3 it hails from Ballydoyle.