Matt Dunn has restored his equilibrium in Highway races in Sydney with Dia De Reyes winning at Rosehill to give comeback jockey James McDonald a first Saturday winner since his return.

The Murwillumbah trainer notched his 15th win in the races for country-trained horses after a lean time this year.

The horse who gave him his latest win has not quite had the career his trainer might have imagined when he ran stablemate Care To Think to a head in a maiden at the Gold Coast in December 2016.

Care To Think has progressed through the ranks and is one of the favoured runners for the upcoming Group One Kingsford Smith Cup and Stradbroke Handicap at the Brisbane winter carnival.

"He has had a few niggling problems but he only just got beaten by Care To Think early," Dunn's wife Keira Dunn said.

"He can also be his own worst enemy because he misses the kick.

"It's great to win another Highway race. We have been beaten up the last few times we have come down here.

"We've gone back to me travelling to Sydney with the horses and Matt going to Queensland with the others.

"It seems to work better."

McDonald positioned Dia De Reyes ($9) midfield and he kicked on the inside late to beat the $2.35 favourite Coup De Main by half a length.

Coup De Main is trained at Goulburn by Danny Williams who is now Dunn's major rival in the restricted races with Canberra horses no longer eligible.

Keira Dunn said she and her husband would discuss the next move for Dia De Reyes.

"He may be able to get out to 1600 metres but he also likes to be kept nice and fresh," she said.

"He looked so good in the yard today and I was surprised about his price."