The pacer was given a perfect run in the one-one by driver John Dunn, and made the most of it by winning race 5.
The victory meant Broadhurst picked up some spending money on the first stop of a road trip to Invercargill.
Broadhurst hoped to start Donegal Carrickfin and The Last Straw, who finished third in race 2.
"We are on our way to Invercargill and hoped to start them there, but Donegal Carrickfin is out of his race now because he won."
Broadhurst said Donegal Carrickfin's victory was a deserved one after the horse had raced in stronger events in Canterbury recently.
"This horse has run Forgotten Highway to a nose.
"He has got a lot of ability when he gets it all right.
"I actually thought he might have been a bit big in condition because I had originally nominated him for the 2200m stand, but it all worked out."
Broadhurst said his phone had been running hot recently with offers from Australian buyers, but he was keen to keep racing the horse.
Donegal Carrickfin's victory gave Dunn a winning double after he won race 3 with Anamajor.
The Canterbury filly Anamajor took advantage of a perfect run in the trail to win and qualify for the $140,000 Nevele R Fillies Final in May.
Anamajor prevailed by a head over runner-up Allaboutdreams, in a thrilling finish to race 3, a series qualifying heat.
The Robert Dunn-trained filly tracked the favourite, Major Sass, throughout.
She appeared to have every opportunity to win and finished a further head behind the first two placegetters in third.
Another Canterbury 3yr-old filly, Bettor Lady, produced a good win in completely different circumstances in race 1.
The Andrew Stuart-trained pacer produced a sweeping finish from off the pace to win with Orange in the sulky.
A decent race tempo over the 1700m set the race up so that Bettor Lady could show her best.
"She is really nice filly, she has got very high speed and she is very well gaited so 1700m around Forbury Park suited her," Stuart said.
Bettor Lady is raced by her trainer with Australian owner, Rob Jones, who races horses across Australasia.
Canterbury junior driver Cameron Jones arguably produced the drive of the night when winning race 4 with Mr Fahrenheit.
Jones launched the trotter, trained by his mother, Leone, for his winning run from mid-field, well before the home bend.
Mr Fahrenheit pinched a big winning break by the time he got in to the straight and could not be caught by runner-up Sioux Princess.
Jones said the horse's drop back in class from racing open-class trotters in his recent starts was the key to the victory.
"He was in against Kings Landing last week and had been racing Ronald J and Didjabringthebeers - horses like that.
"Don't get me wrong, he had not been going that great - but it was big drop back."
Tahakopa trainer Brian Norman produced arguably the training performance of the night when Ace Commander won race 6.
The trotter had not raced since June of last year before producing a big fresh-up victory in race 6, last night's feature trot.
