Millwall interim manager Adam Barrett was unimpressed with the officiating against Blackburn Rovers, labelling Joe Rankin-Costello’s goal offside and insisting they should have had a penalty.

Rovers beat the Lions 2-1 at The Den with goals from Rankin-Costello and Callum Brittain turning the match on its head. Millwall had led from the third minutes through Wes Harding before Rovers levelled the score midway through the first half.

It was a free-flowing move down Rovers’ right, with the two goal-scorers exchanging passes and Rankin-Costello finishing from 15 yards. However, Barrett felt the goal was offside.

The Millwall stand-in boss also felt his side did enough to win the game, let alone avoid defeat. The hosts naturally chucked men forward in the closing 20 minutes but Leopold Wahlstedt didn’t have too many saves to make. Compared to Bartosz Bialkowski, he was the least busy of the two goalkeepers.

“Obviously one of frustration because we definitely did enough to win the game, especially second half when it was all us really,” Barrett said “Little bits I’m not happy with. I wasn’t happy with the build-up or the defending to [Blackburn’s] first goal.

“I’ve seen it back and I’m not here to make excuses but it’s offside. The first goal was offside. So again, little key moments don’t go your way. We get a big shout for a penalty on Tom Bradshaw, doesn’t go your way. And like I said, little key moments in games.

“Second half was much better. We wanted the lads to play quickly, we wanted them to move the ball with a little bit of spark and first half at times it just looked a little bit edgy. Even there was some good bits like the shape.

“You have to be careful against this side because as we know they’ve got some very, very good players and if you get it wrong, they can open you up and with the second goal … Joe takes the free-kick, goes down a groin injury and all of a sudden they break and they go straight down that side where he would have been.

“So little things just didn’t go for us tonight. There were a lot of positives, especially second half. What we’ve got to do now – and we had it at Preston where we had good spells in the game – we now have to do it for longer periods in the game. But it’s been such a quick turnaround, different messages, the lads showed the effort second half and kept going and kept pushing but we have to start being more ruthless in both boxes and that’s something we have to get better at now.”

Barrett also felt Millwall should’ve had a penalty when Hayden Carter tangled with Tom Bradshaw in the box. The Rovers defender appeared to try and pull out of what would’ve been a late challenge.

The striker went down in the box but referee Andy Davies waved away the appeals, much to the fury of The Den. Barrett was bemused at that decision and was particularly frustrated with the offside call for Rovers’ opener.

Asked for his view on the refereeing performance, Barrett said: “I’m not here to make excuses but it is just frustrating when there’s quite a few key decisions that went against us tonight because they’re big moments in games and they change momentum. The first goal was offside – the linesman’s right there. I can’t believe how you can’t see that.”

“The penalty – I’ll have to see it again but everyone by all accounts is saying it’s a penalty. Another big moment. But we’ve got to take that aside as there were bits I was pleased with and there’s bits we have to get better at and we have to get better for long periods of the game.”