. . . and White converted his advantage.

The most direct approach to gain further entrance on the queenside and eliminate Black's attacking bishop. True, White is very comfortable, having made considerable headway on the queenside already.

The attempt to preserve the bishop with 22...Bd7 runs into 23.b5 Rxa1 24.Rxa1 Rh6 25.Nc6 Qe8 26.Ra8 when Black's
attack is not strong enough.

Now White is ready to enter Black's position on the queenside, while a black attack on the other side has lost considerable sting now the light-squared bishop from c8 has disappeared. White converted his big advantage.

Black targets the a4-pawn. Well, it seems that Kasparov has said that in general, a knight on f5 is worth a pawn. So,

Making way for the knight, en route to f5!

27...Qxa4 28.Nd4 Qb4 29.Rc3 a4 30.Nf5

The killer knight.

Now it is over. White took on c4 and won after a few more moves.

You guessed it!