Paul Hartley was left to lament his side’s defensive errors as Cove Rangers’ promotion hopes were ended by Airdrieonians.
Cove were unable to hold on to leads during the game, with Mitch Megginson and Rory McAllister seeing goals cancelled out almost immediately by the hosts.
Callum Gallagher and Jack McKay levelled on those occasions, with Gallagher delivering the winner in extra-time.
Hartley, who was sent off at the death after protesting a late penalty appeal, said: “It’s a sore one. We’re really deflated and low. We put so much into the game.
“We just couldn’t hold on to the lead. We didn’t defend properly with the three goals that they scored. We’ve only got ourselves to blame for that.
“We didn’t defend well enough, we didn’t manage it. That’s what cost us.
“I feel for the players. It’s been a stop-start season for them and we just couldn’t get over the line.”
It took the drama of extra-time to settle this tie, after the teams had four previous tightly-fought contests.
While losing in the manner they did will hurt, Cove can take credit for how they acquitted themselves in League One.
In their first season at this level they finished third and achieved wins over full-time teams for the first time in their history. They also caused an upset in the Scottish Cup by knocking out Alloa Athletic.
He added: “It’s been a good season. It’s tough in League One. We’ll pick ourselves up.
“It’ll hurt for a few days, but we’ll dust ourselves off and go again for pre-season in five weeks.
“Hopefully we can add one or two bodies. Some players will go back to their parent clubs.”
Hartley hopes for a degree of normality to return next season, with a regular calendar and supporters allowed back in grounds.
He added: “Having supporters back and a little normality will be good. It’s been tough with the protocols and financially it’s hit a lot of clubs.
“We’ll pick ourselves up – these players have not suffered too many lows in their careers at Cove. It’s how you come back from that.”
Airdrieonians will have the first leg of the play-off final at home on Tuesday, with the return leg at Cappielow next Friday.