Darren Ferguson declared the 3-0 defeat to Walsall as the 'worst performance of the season' and said he never saw it coming.
Rovers were more than comfortable for the first hour of the game but were blitzed out of sight in a four minute spell where Erhun Oztumer scored twice.
And substitute Kieron Morris put the game to bed ten minutes from time.
Ferguson was fuming after the game and says his team collapsed after falling behind on 62 minutes.
"It was an incredibly disappointing performance and a terrible result, a disappointing day," he said.
"They say nothing much surprises you in football but that certainly did. I didn't see that coming.
"We had a few shots and a bit of the ball but overall I thought it was a real lifeless performance from us.
"The first goal was a horrendous mistake and after that we just went.
"It would have baffled anyone that has watched us all season, that sort of performance.
"It's the worst performance of the season, the worst result of the season.
"Given the opportunity we felt we had to get back-to-back wins, three successive home wins - I don't know where that came from.
"I've got to find answers to it.
"I feel the fans have stuck by us in the main because they've seen performances that have probably deserved more but not today.
"It was a lifeless performance."