The rising five-year-old was having her first start for 12 months when successful in Wednesday's Mypunter.com Plate.
The mare, who was having her first start for Begg after beginning her career with Tony Pike in New Zealand, was backed from $11 to $6 before charging home for a 2-3/4 length win.
Begg said a lot of work had gone into getting the mare into race trim.
“She had quite a few issues in New Zealand with feet and immature knees,” Begg said.
“(Owner) Jonathon Munz was a bit undecided what he wanted to do with her so he gave her a bit of time.
“She bulked on the weight and was up around the 600 kilo mark when she first came to me but we were able to trim her down nicely.
“I think she's a very exciting prospect going forward because if she can run up to her pedigree we can make some plans for her.”
Begg said Munz went to $410,000 to buy the half-sister to former handy stayer Epingle as a yearling.
The trainer conceded time may be against him for the mare to be a spring contender but believes there's plenty of improvement to come.
“She's a city winner now which important, but some black-type down the track would be ideal,” Begg said.
A half-sister to Group One winning sprinter Griante also broke her maiden status when successful in the Ladbrokes Cash In Handicap.
Grand Wish, prepared by Griante's trainer David Brideoake, will be given the opportunity to head towards the better spring races following her narrow win.
Brideoake said whereas Griante was purely a sprinter he believed Grand Wish could develop into a talented 1600m-horse.
“She's got a good racing technique so let's see where that takes us,” Brideoake said.
“We all like to aim at the Thousand Guineas. We're off-season now but she's an improver and a powerful animal.
“We'll space her runs, try and get a Saturday win and see where we end up.”