Preventing f4-f5.

A senseless sacrifice; but after:
5.Bxe7 Nxe7 Black is also clearly better thanks to his superior minor piece.

A sound extra pawn up, Black went on to win without major problems.

Preventing Black's only active idea, ...Na5-c4. Besides which, a doubling of rooks with Rbc2 is enabled.

1...Ra7 2.Rbc2 Raa6 3.Kh2 is similar.

Preparing a kingside advance with g2-g4, f2-f4 and f4-f5.

This simply drops a pawn. Preferable was 2...c6 with just a slight disadvantage – Yusupov.

With a sound extra pawn, White went on to win.

White has managed to isolate the enemy rook on b7.