1...Be5? 2.f4 the bishop leaves the board under worse conditions.

2.Rxf2 Qa5 3.Qe2! f6 4.Qb2 Rf8

Black is just one move from dislodging the knight by ...c7-c6; however...

Insisting on the g4-g5 idea.

White has a decisive attack.

Eliminating Black's most active piece, after which his underdeveloped queenside will become more notable.

With the double threat of 4 Rxd4 and 4 Re4.

With the decisive threat of 7 Re8+. White won just a few moves later.

Trying to exchange, or at least dislodge the active black rook.

Or 1...Rxc1 2.Rxc1 Bd6 3.Na4! , heading for c5 or b6, when 3...Bxf4? fails to 4.Qxf4.