Neil Harris says his Millwall side "won't be fooled" by Sunderland's League position ahead of Saturday's clash.
The Black Cats are bottom of the Sky Bet Championship, without a win in seven outings and will be 'scrapping for their lives' at The Den this weekend.
"They've had to face adversity this season but they have had some strong results recently and some good come-backs," Harris told millwallfc.co.uk
"We will not be fooled as a group - it will be a tough one because Sunderland have some really good players.
"We have confidence now, not an arrogance, that we can go and win football matches. We are in excellent form. We are four months now unbeaten at The Den and eight games unbeaten in the League.
"To keep our unbeaten run at The Den is key for us and we will have to be at it."
Millwall haven't let the conditions interrupt preparations, training in the snow and rain ahead of what's expected to be a bitter afternoon in SE16 on Saturday.
"It's been a really interesting week so far," Harris added.
"Coming in and seeing how the weather is and training in the snow. It takes a different mentality to deal with things like that and the players have attacked it brilliantly.
"The results that we have had in the second half of the season have been outstanding but it's no good looking back at the last few months - we have to look forward to the next few months until the end of the season.
"I want to reach that 50 point mark as quickly as possible and we have the opportunity to do that this weekend."