A campaign marred by wet weather has turned into a blessing for Youthful Jack as the no-nonsense sprinter scored an upset win in the $150,000 Ramornie Handicap at Grafton on Wednesday.

Appreciating a hectic tempo set up by Adebisi and Big Bonanza, Youthful Jack swept home from the back to win one of country NSW racing's biggest sprints by a length at $31.

But if it wasn't for the weeks of rain leading into Grafton, Youthful Jack might not have even taken his place in the Ramornie field.

Trainer Ross Stitt was eyeing a support race during the carnival but he was forced to revise plans because of missed racing opportunities.

It mattered little to Youthful Jack, a rising eight-year-old but the only million-dollar earner in the Ramornie.

Jockey Robert Thompson allowed his mount, one of the outsiders in the field, to find his rhythm at the back of the field and when the leaders were stopping, Youthful Jack rallied to beat Big Bonanza ($6) with Pentasia ($9) a half length away third.

"When I saw the speed in the race I gave him a chance," said Stitt, who has been trying to win the Ramornie since having his first runner in the race 15 years ago.

Thompson, who has ridden more winners than any other jockey in Australia, could only marvel at a horse who has won 18 races up to Group Two level.

"He's been a bloody great horse," Thompson said.

"I've won a heap of races on him right back to when Allan Denham had him early.

"He was probably eight lengths off Big Bonanza (at the top of the straight) but the old boy let down."

Big Bonanza and Adebisi were responsible for a frantic tempo and they headed for the finish with a clear margin over their chasers.

Adebisi was the first to crack and Big Bonanza stole a break only for Youthful Jack to emerge from the pack with his winning run.

Last year's winner and favourite Howmuchdoyouloveme ($4.40) followed the leaders but he couldn't find a finish good enough under his 60.5kg in winding up fifth.