A nasty incident in the mounting yard at Benalla has cost apprentice Matthew Cartwright the opportunity of riding a winner for his mother and grandmother a day later at Sandown.

Cartwright fractured his ankle in the incident on Tuesday and was due to have surgery on the injury around the time the Lyn Tolson & Leonie Proctor -trained Triggerific won the Ladbroke It! Plate (1300m) on Wednesday.

With Thomas Stockdale aboard, Triggerific ($11) scored a half-length win from the $1.80 favourite Skywriter with Tass ($5) a length away third.

Cartright’s mother Leonie Proctor said her son would be bitterly disappointed at having missed out on the win on Triggerific.

“He’s not going to be too happy after that,” Proctor said.

“He’s had a good opinion of the horse, but he’s just taken a lot of time to work it out.”

Proctor said Cartwright was lucky to escape the incident at Benalla with only the ankle injury.

She said Cartwright was likely to be sidelined for as long as eight weeks.

“He’s been very lucky through his career so far, touch wood,” Proctor said.

“The horse reared up and flipped on top of him and then it scrambled all over him as it was getting up.

“It was a very nasty incident, and he was lucky to just come out of it with an ankle injury.

“They said eight weeks depending on the break. We’ll get him doing his rehab.”

Cartwright completes his apprenticeship in October and was closing in on outriding his metropolitan claim having ridden 72 winners to date.

Proctor hopes Triggerific can progress to better three-year-old company than the maiden race he won on Wednesday.

“He’s taken time to work it out mentally. He’s getting there,” Proctor said.

“We’ll look at stepping him up to 1600 metres and we’ve earmarked a few nice staying three-year-old races. Hopefully we’ll get there.”