Pompey were trailing 2-1 when John Mousinho made his final throw of the dice by bringing on Christian Saydee.
And it proved to be an inspired decision as within a couple of minutes, he drew a clumsy challenge from John McAtee in the box.
Refeee Paul Howard pointed to the spot and Colby Bishop stepped up to confidently convert the penalty.
We all know what happened next, of course, as Conor Shaughnessy headed home a late winner to secure the League One title.
Saydee was thrilled to play his part in a momentous occasion on the south coast and help the Blues into the Championship.
He said: “As soon as Marlon rolled the ball inside, I saw the gap and just tried to get my back into the defender and do what I’m good at.
"To complete what we set out to do is an incredible achievement and it’s tough to find the right words to describe it."
“He’d actually been giving me a bit of stick about a minute before that, so I was pleased that he then fouled me for the penalty.
“I’d felt so weird watching from the bench – probably the hardest one since I’ve been here – but we got the job done.
“It’s so brilliant to win the title and we all knew what we were signing up for when this squad was put together over the summer.
“To complete what we set out to do is an incredible achievement and it’s tough to find the right words to describe it.
“Our fans have wanted to see this club in the Championship for a number of years now, so I’m delighted for them.
“They have been behind us right from the very start and so this success is for them. They really deserve it.”
