Tony Mowbray is expecting a fascinating contest when Rovers head to the capital on Tuesday night to tackle Millwall at the Den.
The Lions sit three places and two points above Rovers in the table, helped by their weekend win over Hull City at the KCOM Stadium.
Like Rovers, Gary Rowett's side will also have their eyes on the top six prize with only three games remaining of the season.
And ahead of the contest, Mowbray's expecting an intriguing test, with a draw probably not helpful to either Rovers or the south Londoners.
“Millwall are a different kettle of fish for us. They have some talented players and you underestimate Millwall’s technical footballers at your peril," he told iFollow Rovers ahead of the game.
“You also have to be mindful of their long throws coming into the box, the big centre halves up there, Matt Smith up front is a huge physical presence.
“It should be a good game and there’s a lot at stake for both sides. The Den at its best and noisiest is a really intimidating place to play.
“It’s not one of these stadiums that has 30,000 or 40,000 supporters in it, there might be only 10,000 or 12,000 in there, but what a noise they make," he added.
“There’s a real droning noise at times and the whole stadium does it, which really lifts their team.
“That won’t be there on Tuesday night, but I’ve always felt that to play for Millwall you have to be a certain type of personality, a certain type of character to live with the scrutiny of their support base.
“So their players are made of strong stuff and we’ll have to go there and compete with them."