Bristol City boss Steve Cotterill says his side would not have won with 12 men during Tuesday's 4-0 defeat by Derby.
Tom Ince hit a hat-trick before Johnny Russell headed home to leave the Robins with just one win in six and one point above the Championship drop-zone.
Cotterill admitted there was a noticeable gulf between the two sides, with Derby now two points off top spot.
"At this moment, we are not good enough to take them on," Cotterill told BBC Radio Bristol.
"We just did not have enough belief to take them on. We did not show enough courage to pass the ball.
"We could not win the ball and when we won it, we kept giving it away," the 51-year-old added.
Cotterill made three changes to the side that won 2-1 at Huddersfield on Saturday.
The visitors held their own for most of the first half until Ince opened the scoring after 42 minutes.
But the Robins manager believes no matter which team he fielded against the Rams, they would have struggled to contain Paul Clement's side.
"I could have had 12 players out there tonight but I am not sure we could have handled them," Cotterill added. "For quite a few of them, it was the first time they have been here (to play Derby) and it looked like it."