Stuck in a lesson of "Silman's Lessons in Strategy (2)"

I am studying "Silman's Lessons in Strategy (2)". I have just passed a lesson "Denker-Smyslov, USA vs. USSR Match 1946" and stuck at the lessons final position: after Nd6 White can play Qe6 and I do not see any satisfactory defence. Any ideas?

Sergey.

6...Nd6 eyes both e4 and c4 and wins a pawn as a result. White is now positionally lost and he resigned the game (after huge material losses) in another dozen moves.

after Qe6, i think black would play Nxe4, protecting f6 pawn.

After rook retreat, let's say black can exchange queens, and chop the e6 pawn. Or, white has to trade queens himself. still, nothing to worry for black, they can defend f6 with second rook, and come back with night to d6, hitting the next pawn, which seems to be not defendable..

am i missing something ?

No, it seems that I was just overtrained. =)