EDDIE Howe says Millwall's recent track record at Turf Moor gives Burnley cause for concern ahead of Saturday's match.
The Lions have won 3-1 and 3-0 on their last two visits to Lancashire and Howe says those results "make us aware of the difficulty of [this] league."
The Clarets are looking to bounce back after a midweek defeat to Swindon Town in the League Cup but Howe is only too aware of how difficult that will be against Millwall.
“You only have to take a look back at the last two seasons for us to see it’s going to be a very difficult game," he told the Burnley Express.
"They are a tough nut to crack, very physical, a real threat from set plays, so we won’t underestimate Millwall. You know what you can expect every time you play them.
“We’ve certainly got to perform better than what we have done in the last two home games against them. Those results make us aware of the difficulty of the league.
"Everyone associated with Burnley will see this as a must home win, we certainly share that view, but that doesn’t go to say it’s going to be easy.
“All Championship fixtures are tough. Millwall are very well organised and well managed by Kenny Jackett who has done a fantastic job there down the years.
"They haven’t changed a great deal from last year, so we’re still wary of their threat.”