Tony Mowbray was critical of assistant referee Andrew Halliday after Rovers bowed out of the Emirates FA Cup against Newcastle United, after extra time.
Rovers battled back from two goals down to go into extra time with the scoreline at 2-2, through goals from Adam Armstrong and Darragh Lenihan.
Joselu bagged Newcastle's third of the night on the stroke of half time, in the fourth minute of two added minutes, and blatantly offside.
Substitute Ayoze Perez added gloss to the scoreline later on, which was unfair on Rovers, who bossed the majority of the encounter.
And the boss was fuming with Halliday's call when reflecting on the match afterwards.
“The third goal is offside, and that’s a big thing, not a little thing, that didn’t go our way," Mowbray revealed to iFollow Rovers post-match.
“We missed a great chance at 2-2 when Bradley [Dack] slips a shot past the post rather than into the back of the net.
“It was a great effort from the players, and I feel for them."
"It wasn’t until this afternoon that we knew we’d play with three at the back, with Rodwell and Downing being ill and not being able to make it, as well as [Charlie] Mulgrew and [Derrick] Williams being injured.
“We were left with one centre half and had to concoct a defence.
“We lost goals early on, and I think that was why. The character and the spirit was there for all to see, but I feel we were let down by the linesman, particularly with the third goal.
“You have to go chasing the game in those final 15 minutes and we lost the last goal through that. That’s football.
“Over the two games, I feel we matched Newcastle and caused problems for them, but it wasn’t to be.
“We’re left disappointed, because at 2-2 it was a game I felt we should have won. Ultimately we let it slip through our fingers.
“We’ll put the result behind us quickly and get ready for two home games, two good games for us to have."