Tony Mowbray believes his team "have to be better" to challenge at the top of the Sky Bet Championship, despite the 2-1 win over Millwall making it three victories in a row.
Winger Harvey Elliott, on loan from Liverpool, struck a spectacular 25th-minute opener before Scott Malone scored a superb equaliser nine minutes later.
The game looked to be heading for a fair point apiece before Adam Armstrong hammered home a stoppage-time winner – his 50th goal in Rovers colours.
It means Blackburn are unbeaten in six and sit ninth, just four points off the summit. Yet despite the third successive win, Mowbray felt his team looked "jaded".
He said: "We're obviously delighted, finding a way to win.
"Ultimately we have to be better if we are going to genuinely challenge. What we've found is lots of teams play three at the back, some play with two strikers. Lots of different formations, and what we're finding is we're probably not good enough to just play our way.
"I genuinely felt we looked a bit jaded. I shouldn't say it because it might play on the minds of the players but I felt they were off the pace of where we can get to with the intensity.
"The winning goal was a bit better because you've got (Joe) Rothwell nicking the ball in their half like we've been doing all season and five seconds later it was in the back of their net.
"It's not a surprise to have a jaded performance on the back of all the games. There is lots for us to keep working on."
Millwall boss Gary Rowett was "incredibly frustrated" after seeing his side's three-game unbeaten run on the road end.
He felt his side were on the wrong side of three handball decisions in the box.
Rowett said: "It's an incredibly frustrating evening. The beauty of modern technology is, on the bench, we more or less get a live feed. I appreciate the officials haven't got that ability but that's why they're officials, because they have to make the right decisions, or one of the right decisions.
"The first one with (Darragh) Lenihan, I can semi-understand why they didn't give the first one. The second one, ball in the box and Jon Dadi Bodvarsson has a header, (Daniel) Ayala has both his hands above his head and he blocks the shot with either one of his hands.
"Then the third one, you can see blatantly, Ayala almost punches it out and the referee has a really good view. That's why you see our players going mad about it.
"That's why I'm sat here disappointed. I thought we played really well. I think I should be sat here talking about a game that either we've won or drawn."
