Chris Wilder is under no illusions about the tough afternoon that will await his side in the capital at the weekend.
Speaking ahead of Saturday's trip to The Den to face Millwall, the Blades chief acknowledged his players must be ready to stand up and be counted against the Lions.
Looking ahead, he remarked: "They play in a certain style that gets them results, but perhaps they're performances have been better than their recent results.
"We've watched them a few times, we get all the stats and all the film and they've been very close to winning on a number of occasions.
"They've perhaps lost games they should have drawn and drawn games they could have won.
"It is always a difficult place to go, everyone understands that and our players have to stand up to the challenge that will come."
Wilder added: "We know how they will play, it suits them, our style suits us. If we're not at it we won't get a result, if we are we'll have an opportunity.
"They recruited well in the summer, Saville is a good player, Tom Elliott is a threat at the top of the pitch and the likes of Morison and Gregory are an outstanding partnership.
"They've upgraded following promotion and like us they will be enjoying being back in the Championship."