The point-to-point winner had shown plenty of promise with a number of placed efforts over hurdles and jumped well on this switch to fences in a race for horses rated 102 or less over hurdles.
The Jet Away gelding made most of the running but Blackmore needed to get serious on the run-in to hold off fellow 100/30 joint favourite Final Orders by a length. Majavango was a further three-quarters of a length back in third.
An understandably emotional Blackmore said afterwards, "He did it real well, he ran around a bit at the end. It is great to get but obviously winners don't feel the same now.
"He jumped well and he was brave. He won a point-to-point for Rosemary Connors, so he had that experience coming here today.
"He's a very forward-going type, so hopefully he will improve now for fences.
"We are all thinking of Jack."
This was the first win for the Knockeen yard since the tragic death of de Bromhead's son Jack in a pony race on Rossbeigh beach less than a fortnight ago.