Darren Ferguson insisted Doncaster Rovers only had themselves to blame for missing the opportunity to win the League Two title.
A win at Hartlepool United would have proved enough for Rovers to be crowned champions with Plymouth Argyle held to a draw at Grimsby Town.
But Rovers threw away the lead, after Andy Williams had put them ahead, to lose 2-1 against a Hartlepool side that were ultimately relegated.
And Portsmouth surged in to take the title after thrashing Cheltenham Town.
It ensured disappointment for the Rovers players, despite having sealed promotion in emphatic style.
"It was another wasted opportunity and an incredible opportunity with the way the results panned out," Ferguson said.
"It started early doors, Grimsby must have scored really early and we heard our supporters singing.
"When Willo scored we were in a very good position.
"But we've got no one to blame but ourselves.
"I congratulate Portsmouth and I feel for Hartlepool because I thought at one point they were going to stay up, and they would have deserved to because they deserved to win the game.
"We played into their hands. If you don't keep the ball, it means you're going to defend.
"It was a really poor performance and I can't have any excuses.
"We've ended up finishing third but we've been promoted.
"It's a funny feeling because we've lost the last four. I feel disappointed.
"It's taken the gloss away from it, losing those last four games."
Ferguson criticised his side for failing to handle the big game situation and wilting in the face of pressure from Hartlepool in the second half.
Buoyed by the fact Newport County were being held to a draw by Notts County, Hartlepool's supporters roared their side on which helped spark the turnaround.
"I don't think we handled the game well at all," Ferguson said.
"I thought first half we were ok. I thought second half we were awful.
"A big thing about being a footballer is to have the composure to play in the big games and I don't think we handled the situation at all.
"Play the game and not the occasion. Play the game as we have the whole season.
"We've had big games this season, big games on TV where I think we've played very well.
"But today we didn't handle that side of things. Our passing was so poor."