Thornton steered Happy Go Plucky for little known trainer John Gilmore to victory over Chris Waller trained So You Think at Ipswich Racecourse.
The Gilmore runner was massively unfancied in the betting at odds of $26 to one however jumping from barrier 11 Thornton managed to take Happy go Plucky to the front and kick strongly all the way to the line.
Despite a wave of runners looking to topple the winner in the straight Thornton said she felt like the winner turning into the straight.
“We drew awkwardly which was always going to make it tough for him but he got across well, he switches off and gives himself every chance,” she said.
“I felt like the winner at the top of the straight, I just needed him to hold up and he did.
“He was a happy horse, he looked brilliant in the mounting yard and I thought his last few runs were really genuine. It can take you a long way knowing they are going to run out the distance.”
After a host of southern riders had headed back after the Queensland Winter Carnival, Thorton was looking to make the most of her opportunities.
“It is tough to get on those shorter-priced rides during the carnival but I have been trying to make the most of the opportunities I am getting,” she said.
“I don’t think they’re going to take me off him now, I think I am going to have to keep him whether they like it or not.”
The win marked just the second listed grade success for Stephanie Thornton who won on Sugar Boom in 2019.