Mixu Paatelainen criticised goalkeeper Michal Szromnik for the error that cost Dundee United their first win since October.
Szromnik failed to deal with Carl Tremarco’s cross which allowed Lewis Horner to steer in a late equaliser in a 2-2 draw with Inverness.
United had looked to be the winners when former ICT favourite Billy Mckay put them back in front with eight minutes to go.
However, Horner capitalised on Szromnik’s failure to punch the ball clear, which United manager Paatelainen pinpointed as “stupid.”
John Rankin had given the visitors the lead in the first-half but straight after the break, Liam Polworth scored his first goal for 18 months to level the scores.
Mckay pounced on Owain Fon Williams’ error to nudge United back in front but there was a sting in the tail for the struggling Tangerines as Horner netted in stoppage time.
“We should punch that ball away because there’s pressure on the keeper. It’s so stupid,” he said.
“I don’t think it’s a foul on the keeper. Punch it away and clear the danger, regroup and deal with the next situation. Then the game might have been over.
“You pay the price if you make the wrong decisions.
“One point is better than nothing but three points would have been sweet. We now wait until next week and go again.”
United’s last win came against Ross County on Halloween and they are now seven points adrift of Kilmarnock, who occupy the relegation play-off spot.
Paatelainen added: “We’ve been excellent over the last five or six weeks and today we showed we’ve got some things going for us. But it’s not enough. We need results.
“At the moment we’re not getting results. We’re making mistakes and that comes from stupidity really.
“It’s not fragile confidence – it’s poor decision-making. That’s the standard we are. We take these things on to the training ground and improve.
“We need to improve. It’s not only defending, there’s also attacking situations to improve on. We’re creating chances and scoring goals but it wasn’t enough. There’s plenty to work on.
“There’s no excuse. I don’t think any player will say they’re nervous. It makes them even more determined, ruthless and hungry not to lose that goal.”