Head coach Richard Cockerill described Edinburgh's 34-16 loss to Zebre as "half a step back" following last weekend's rousing win over Toulon.
Edinburgh were missing several key Scotland stars but led by 10 points at the interval in Parma.
However, Zebre ran in four tries as the visitors fell apart in the second half.
"From where we were at half-time to the end of the game, for me, is just not an acceptable performance from this team," Cockerill told BBC Scotland.
With the autumn Tests starting next week, only five players remained from the team that started the 40-14 Champions Cup victory over Toulon but Edinburgh looked on course for a Pro14 success as a Darcy Graham try put them in front.
"It was a really good first half, we played really well," said Cockerill.
"At half-time we spoke about controlling the ball and the game and controlling the opposition because they are very dangerous when they have the ball. But we didn't."
'We got exactly what we deserved'
David Sisi, Gabriele Di Giulio, Carlo Canna and Tommaso Castello all profited from moments of slackness to complete a bonus-point comeback for the Italians.
"We missed one tackle and they score the first one," said Cockerill. "You'd expect an international like Dougie Fife to catch a high ball and not let it bounce. It bounces funny and suddenly they are under the sticks.
"We then fill them full of energy and the game gets away from us. Suddenly you have given them 14 points for nothing.
"You are going to make errors in the game. That happened, but then you have to get back in control of the game.
"We throw an intercept and the game is away from us. They then score at the end and it's a thumping. We got exactly what we deserved and it's not good enough."
Jamie Hodgson, Callum Atkinson, Pietro Ceccarelli and Mungo Mason all made their Edinburgh debuts.
"We've got some guys missing but that's not an excuse," added Cockerill. "We played well enough in that first half and we knew what we were trying to do.
"Some of our senior guys have got to step up. There was some inexperience in the side and they are learning but I expected more.
"When it started to go against us, we didn't have the wherewithal to rectify it, which is very disappointing. This group of players is better than that."