Danny Wilson described Saturday's European Challenge Cup quarter final defeat to Gloucester as "shell-shocking".
Wilson’s side were leading 26-20 early in the second half, but conceded four unanswered tries at Kingsholm, which secured a 46-26 victory for the hosts.
Wilson gave credit to the home side’s clinical attack, but insists his side must learn from their errors in the West Country.
Wilson said: “It was two poor defensive errors and the only way to describe that is a collapse. It’s something we’ll review and take the positives from the first 50 minutes.
“I think we got the gameplan right and executed it relatively well, and then we saw a complete collapse for 50 minutes.
“Ultimately they scored four tries in the second half, and I think the turning point is, after all that pressure, the couple of errors made from us holding high field position and we didn’t get back from there.
“Credit to Gloucester, they finished their tries well and took their opportunities, but far too soft as far as I’m concerned and a 15-20 minute period that’s unacceptable.
“For the first 50 minutes of the game I thought we played some really good rugby, were in control and possibly could’ve been further in the lead.
“To go from 26-20 on 50 minutes, while holding most of the field position at the start of the second half, to what we saw unfold over the next 15-20 minutes was shell-shocking for all of us concerned.
“There were three soft tries in a 15 minute period. The first one comes from us applying pressure at the other end of the pitch, but a poor kick leads to Matthew [Morgan] trying to run out of his 22, losing the ball and they score. That happens in a game of rugby but we should be able to quickly regain control.”