Damien Johnson admitted Rovers 'never really got going' as his Under-23 side slipped to only their second league defeat of the season at home to Brighton on Friday night.
First-half strikes from Viktor Gyokeres and James Tilley secured the spoils for the Seagulls, as Rovers' impressive 11-match unbeaten run came to an end.
Despite the defeat, Rovers remain top of the Premier League 2 table and Johnson is hoping his players respond to the below-par performance in the right way when they return to action away to Cardiff in the Premier League Cup next week.
"I think too many of them just had an off night," said the Northern Irishman.
"It was just one of those games where we never really got going and Brighton deserved the win.
"There's not too many times I've had to say that to them this season. We've normally brought a good level, both individually and collectively, but tonight we didn't.
"They have to realise you can't afford to have too many of them in their careers. You have to really limit them and now the reaction is going to be important.We never
"They're young players and you do get ups and downs, and more often than not they've brought a level of performance, but tonight too many didn't and I can't remember too many times I've had to say that to them.
"It's important that we put it into context. We're all disappointed, none more so than the lads themselves, but we've seen earlier in the season when we've had little setbacks like this they've come back and they've showed their character and togetherness, and they'll need to do that again.
"We'll try to learn as many lessons as we can from this and that's important because sometimes you learn just as much from games like this and knowing the characters we have, the reaction will be right."