Prolific Highway Handicap winner Matthew Dunn broke new ground at Randwick, nailing the trifecta the first time he had entered three runners in the race for country-trained horses.

The concept's most successful trainer, Dunn secured his 12th victory on Saturday when Bronzed Venom ($13) overhauled the favourite Cascata Rossa ($2.30) late to win by a long neck.

Dia De Reyes ($8.50) recovered from a slow start to finish the 1600m trip strongly in third.

The trio will remain in Sydney and providing their recovery goes to plan they will line up in the $200,000 Anniversary Handicap at Randwick next Saturday.

"It's such a thrill to see them one, two, three," Dunn's wife Keira said.

"I'm always confident when Matthew says 'You're going down to Sydney', 99.9 per cent of the time he makes the right choice."

Dunn said she was concerned when Bronzed Venom was boxed in but Brenton Avdulla bided his time.

"It looked a little bit ugly for him but once the gap did come the horse had a great turn of foot," she said.

Dunn became the second trainer to record a trifecta on Saturday after Chris Waller had all three runners Alward, Up 'N' Rolling and Veladero cross the finish in that order in a Benchmark 90 Handicap.