Help needed

http://www.chess.com/livechess/game?id=347160870

This is a game i played. I understand move 21. ...a5 is a mistake. But how could have i proceeded. Please do reply if you have the time.

Thanks in advance,

Nandakumar

I'll try and get back to you. In the meantime as a premium member you can have chess.com analyze the entire game for you their analysis isn't great but it's way better than nothing and you'll be surprised at all the stuff you and your opponent probably missed (I never cease to be surprised at all the stuff me and my opponents missed in the games analyzed by the chess.com PC)

To me, the previous move looked questionable. Why did you take the b-Pawn with your well-placed Nd5 instead of using the Nc6 for that?

I know i have not been playing the perfect move each time. Please point out my mistakes blueemu