The son of Oaks Road and Aella began well from box one but was beaten for speed in the run to the first turn by Victorian raider Shared Equity (box six) and fellow local Tiggerlong Await (box five).
The black dog was able to push up along the fence through the pen to hold third spot, but lost ground heading into the back straight when checking off the heels of Tiggerlong Await as he tried to go for the inside run.
With no run on the fence, Ima Wagtail switched to the outside of the leading pair swinging for home, unleashing a powerful finishing burst down the centre of the track.
On the line the judge had to call for a photo to split the trio, with Ima Wagtail prevailing to score by a nose over Tiggerlong Await, with Shared Equity just a neck behind that pair back in third.
Ima Wagtail has now won eight races from 36 starts, with the $150,000 winners cheque taking his career earnings to a sizeable $173,955.