The Argie hit the post late on in the 1-0 triumph.
"In a top team there are 11 players," said the Italian.
"But if we want to win and improve, we need to have 20 good players that have a good attitude.
"Pablo is a very clever player.
"He knew before the game it would be difficult. I told him if he played very well against Theo Walcott we would probably win the game."