Billy Barr admits big improvements must be made ahead of Rovers' Under-18s FA Youth Cup fourth round clash against Leicester City.
The Rovers chief expressed his disappointment after the 1-0 third round victory over Southend United.
In an action packed tie at Ewood Park, the solitary strike came in the second half when Willem Tomlinson broke the deadlock from the penalty spot.
Both sides were also reduced to 10-men, Abdul Salami seeing red for a foul on Lewis Mansell whilst Rovers' Josh Askew was given his marching orders for an off the ball incident with Daniel Walker.
It was a battling victory for the young Rovers, however Barr felt his side didn't match their usual high standards.
"I didn't think it was a very good performance and Southend were more than a match for us," said the Under-18s boss.
"We were really sloppy and the lads have been told that, we've set standards higher throughout the season and against Southend we didn't adhere to them.
"We need to raise our game against Leicester City. We went to watch them against Cheltenham, they are a strong and powerful team.
"We'll go in to the game and we'll do our work on Leicester, hopefully we'll get a better performance out of our lads.
"Now we'll just take one game at a time, we are very fortunate to be in the next round so we can't look too far ahead."