The Cornish Sharks hopes of making the play-offs have been boosted after they ended Berkshire Renegades unbeaten run with a dramatic 30-27 win in Newquay.
Adam Kevern's touchdown from a yard out with three minutes to go was enough to take victory in a see-saw match.
The Sharks were 13-12 down at half time and 27-24 down with three minutes to go before MacIntyre's late touchdown.
The Sharks defence then held firm against Reading to seal the win.
"Everyone did us proud, and never write the sharks off. They did, they thought we were done," head coach Brian Smallworth told BBC Radio Cornwall after the match.
"That's their perfect season finished - when you come to the Shark tank you're going to get beaten," he added.
And Smallworth is confident that his side, who are third in the British American Football Association's Division Two West, can overtake second-placed South Wales Warriors and make the play-offs.
"We'll beat Wales at home and we'll beat Gloucester," Smallworth said.
"We'll rack scores up on Gloucester big time and then it's going to be down to one of the teams who'll cough and splutter."