Ospreys suffered their first ever defeat to Connacht on the weekend, after which assistant coach Gruff Rees described their performance as "unacceptable."
Bundee Aki inspired Connacht to a 21-16 win at the Liberty Stadium on Saturday. The result pushes Steve Tandy's men down to tenth on the in the PRO12 standings, with just one win next to their name.
"We're hugely disappointed…that display was borderline unacceptable and we've told the players that after the game," lamented Rees on pro12rugby.com.
"They have to realise they are accountable. There were schoolboy errors on the pitch but as coaches we are also accountable to drive standards.
"It's a low point in terms of the result but also the endeavour and application in the performance.
"There were a huge amount of individual mistakes, but we also lacked shape and went off-task with a lot of things. In the first three games we were outmanned but that wasn't the case today. We were out-thought and out-fought.
"There was naivety about our back play – we didn't respect the opposition or the ball and tried to force things. We have a lot to work through this week before going to the champions Glasgow next week."
Ospreys next travel to Scotstoun Stadium where they face the Glasgow Warriors in round six of the competition on Sunday.