Even after seeing all the analysis, this patzer still doesn't understand why this was not somewhat premature resignation by Gelfand. After 17..Nc6, in material terms he ends up with a rook and 2 pawns for the pair of knights. Ok, I know black's position is supposed to be a shambles and Fritz 9 (given an airing after several years) gives an evaluation of 1.38 which is a virtually certain loss at this level, but could Gelfand really not have played on a bit longer. Unless, of course, he was so shocked by 17 Qf2 that he could not focus and didn't see Nc6.

against a king with broken pawn structure

the -1.5 that the engine gives, which is merely counting material,