Developing a piece and putting pressure against c5.

White doubles heavy pieces on the a-file to put tremendous pressure against a7.

Passed pawns are also important at the endgame, and even more those who are far away from the king and the rest of pawns. With this sacrifice, Sargissian creates a passed pawn that will leave the knight pretty tied to the rim.

1...Bd8! This was the move that put up more resistance!
1...axb4 2.a5 Kg7 3.a6 Kf8 4.a7 Nb6 5.Ba6 Followed by Bb7 at some point, winning a whole piece.

Please note how the black passed pawns (b4 and c6) cannot be pushed and even restrict the black pieces. On the other hand, the white knight and bishop occupy the best squares, attacking and defending simultaneously!

Now we create another passed pawn in the center of the board and involve the king in the action (Kg3-Kf4).

White ended up winning pretty easily.