He failed to earn a win for his previous trainer but Zouzoom showed enough fight late on to break through at Dubbo Turf Club on Tuesday.
Only three hopes contested the opening event of the annual Melbourne Cup day meeting, the Australian Community Media CG&E Maiden Plate (1200m), but the finish was a close one as Zouzoom saluted for veteran Gilgandra trainer Bruce Parker.
Tuesday marked the grey gelding's first start for Barker after he had scored just one placing in nine starts for Clint Lundholm previously.
Kieran Hazelton, Parker's grandson and part of the trainer's team at Dubbo on Tuesday, joked the win had been a long time coming for the five-year-old's owners.
"It's good for them though because they've put work into him," he said, Zouzoom having debuted back in February of last year.
"We can't take too much credit for this though. Clint trained him early on and did all the work and we've only had him for a couple of months but hopefully he'll go on with it.
"He's a pretty easy horse to train and doesn't have too tricks."
Despite the small field jockey Anthony Cavallo had plenty of work to do with Zouzoom.
Cavallo settled down second with his $2.70 chance ahead of Arraign ($3) while Chelsea Ings shot out to the lead aboard Carnegie's Monaco ($1.70 favourite).
The Terry Fahey-trained gelding stayed in front into the straight but Zouzoom, who had been throwing his head around early on, soon worked his way forward around the outside of the leader.
The two went stride-for-stride for much of the straight but Cavallo got his hope to kick and he went on to win by a head.
"Choc (Cavallo) is a good, old honest jockey and he won't let you down," Hazelton added.
A step up in distance is now likely for Zouzoom.
Elsewhere on Tuesday, Rodney Robb backed up his Derby Day treble with another Dubbo win.
The popular Nyngan trainer was a standout at Saturday's meeting and delivered again on Melbourne Cup day as Relaxed carried the top weight to victory in the Mailbox Shopper Benchmark 50 Handicap (1600m).
Apprentice Clayton Gallagher again did the job for Robb, having ridden all three of his winners on Saturday.
Relaxed was backing up from Saturday, where he ran third behind stablemate Bells 'N' Bows, and after carrying 57.5kg there he was lugged with 63kg on Tuesday.
It failed to stop the six-year-old gelding though, the $2.50 favourite edging out Carinda Road ($3) and Bel Attrait ($6).
The other winning trainers at Dubbo on Tuesday were Gayna Williams, who had Griffin's Gaze ($3.60) salute in the Daily Liberal Benchmark 50 Handicap (1200m), and Coomble's Ian Holland, who won with Turramurra ($8) in the Dubbo Domain Class 2 Handicap (1400m).