Improved barrier manners have helped Dia De Reyes live up to his potential in winning the Highway Handicap at Randwick.

Notoriously fickle in the starting stalls, Dia De Reyes jumped on terms with the field to ease the anxieties of Murwillumbah trainer Matthew Dunn's wife Keira.

"Just to be in front of a couple was exciting," she said.

Dia De Reyes ($5.50) was 2-1/2 lengths clear at the post to record just the second win of a 14-race career.

Dunn thanked Racing NSW stewards for allowing Dia de Reyes to line-up in the 1800m race on Saturday after he was issued with a warning at Randwick on October 7.

Dia De Reyes missed the start by three lengths before recovering to round out a Dunn trifecta with Bronzed Venom and Cascata Rossa.

"They could have barred him and that only puts the owners and everyone else out of pocket. By letting us go again, it's given our owners another win," she said.

Sovereignaire ($13) led the chasers and Dalmatia Prince ($11) was three-quarters of a length third.

It was the Dunn's 13th Highway Handicap win since the concept for country horses started in October, 2015.