As Shootoff confirmed his Queensland Derby credentials at Canterbury on Saturday, 2007 winner Empires Choice broke down in the same race and had to be euthanased.Shootoff backed up his last start win in the Frank Packer Plate with a dominant performance in the $100,000 Lord Mayor's Cup (1900m) against older horses, but it was a sombre mood post race after Empires Choice broke down passing the 600 metre mark.The seven-year-old son of Redoute's Choice scored the biggest win of his injury-plagued c

As Shootoff confirmed his Queensland Derby credentials at Canterbury on Saturday, 2007 winner Empires Choice broke down in the same race and had to be euthanased.

Shootoff backed up his last start win in the Frank Packer Plate with a dominant performance in the $100,000 Lord Mayor's Cup (1900m) against older horses, but it was a sombre mood post race after Empires Choice broke down passing the 600 metre mark.

The seven-year-old son of Redoute's Choice scored the biggest win of his injury-plagued career in the Group One Queensland Derby (2400m) four years ago.

"He was a good horse, you don't like to see them go like that," Empires Choice's trainer Bart Cummings said.

Empires Choice was ridden by Brad Pengelly who crashed to the turf but was cleared to continue riding at the meeting.

Stewards opened an inquiry into the incident in which Empires Choice broke his near hind cannon bone.

Shootoff was second favourite for the Queensland Derby prior to Saturday's race and trainer Graeme Rogerson's Sydney foreman Roger Elliott said the son of Duelled could head into the Classic at Eagle Farm on June 11 without another start.

"He's going to the Derby for sure," Elliott said.

"He's nominated for the Doomben Cup as well so whether he goes there first or goes straight to the Derby will be up to Graeme."

Shootoff enjoyed the perfect run under apprentice Josh Adams as the three-year-old sat one out and one back with Mr Clangtastic setting the pace.

Adams allowed the gelding to stride from the 500 metre mark and he quickly moved up to challenge the leader.

Shootoff ($4.60 fav) put his rivals away in the straight and had 2-3/4-lengths to spare over Mr Clangtastic ($6.50) with Vision And Power ($9.50) a half-neck away third.

Elliott said a change in tactics in recent outings had helped turn the talented galloper's fortunes around.

"He's learned how to race now while before he just thought everything was a big joke," Elliott said.

"He was just going around for the fun of it.

"We changed tactics to try and make him race a bit more forward to get him on the ball and it seems to have worked."

The feature win brought up a race-to-race double for Sydney's leading apprentice after he guided Break Card to victory in the Canterbury Bankstown Express Handicap (1550m).

"He won the Group Three (Packer Plate) on a heavy track and everyone had him pegged just as a mud runner," Adams said of Shootoff.

"Obviously he's not and on that he can go up to Brisbane and very competitive."