20.Rb3 Overprotecting the knight and freeing the bishop in c1 from the defense of b2.
20...Qe8 We see now why it was better to put the queen directly in b7, now black has to spend an extra tempo to bring the rook to b8. 21.Qc2?! Poor move. It unpins the knight, but the knight needs protection in any case, and if properly prapered the advance c4 is dangerous for white. It was high time for white to finsh his development with Bd2, planning to go to c3 and challanging black's Indian bishop.
21... Rb8 Black immediatly points out how poor white's previous move was.
22.Qe2?! White wants more space for the queen, but alas the lady's position is indeed in c4, blocking possible advances of c5.
22...Qd7 Black already had the option to a big exchange in b5, leaving white with a weak doubled pawn in b5. This move is good too because it makes room for the rook in f8 to enter the fight on the queenside.
23.Bd2 Black is still better, but white is finally getting his act together and mobalizes his pieces.
23...Rfc8 Offering a pawn in exchange of his chance to play c4.
24.Qc4 I like this better than taking the pawn, although this is the cristal clear proof of how many tempi white wasted in the previous moves. His position changed only in the development of the bishop to d2, which he could have done immediatley, while black had the time to increase the pressure on b5 and bring the other rook to the attack.
24...Rb6? Now, this is probably just an oversight. White gets a pawn with tempo. Black was anyway sacrificing his b5 pawn, but for more than enough compensation after (24. ... Rb7 25. Bxa5 Rcb8). A tempo can make quite a difference. By no mean black is losing now, the position is very complicated and white will be hard pressed in holding to the extra pawn.
25.Bxa5 Rb7 The rook goeas where it should have gone in the first place.
26.Bc3 The bishop challenge the Indian bishop, reducing the weakeness on b2.
26...Rcb8 27.Bxg7 continuing on his plan, since nothing can be done to not lose a pawn in the exchanges.
27...Kxg7 Avoiding complication and retaking immediatley.