[Dean doesn't actually remember anything past Sam saying, "Yes". But he's talked to Balthazar and he compared notes with the first Sam that had been here. And the second one. He knows enough about how things eventually go down to bluff his way through this because there's pretty much no way in Hell he's going to willingly tell Lucifer, of all people, how much he remembers.]

I remember that Sam's stronger than you. And I remember that you fail, in the end. You're back in the cage and I've still got my brother.

If you want a fight, come find me. [The flames on his arm, jump a little higher. A reminder that Dean has his own powers now and can even the playing field just a little. Of course, Lucifer can't actually find him, but all he really needs to do is ask.]