Keita was there to keep Milan from scoring. Looking at the score, it looks like it was a sucess.
As for Barça not scoring, I'd first look at Messi, Alexis, Iniesta, Xavi, Tello, Pedro and Alves. It was their job to make things happen, not Keita's.
Just because we did not concede today (something that could easily have happened if Ibra, Robinho and Urby were clinical) proves absolutely nothing about Keita.
I know what the scoreline was, what I want the Keita supporters in here to tell me, is what he did today? What did he do individually? What did he do during the 90mns of play, either offensively or defensively.
You all come up with vague statements like: "he shielded our back 4" or "he brought steel in the middle"
Where exactly was the steel and where exactly was the shielding? If I ask you for one notable interception, or a significant forward pass, or a run, you can come up with precisely nothing, zilch, zero. He did not do anything the entire 90mns other than giving the ball away.
And you are disappointed with Messi, Iniesta, Alexis Xavi etc, and not with Keita? Imagine if you were advising some football team anywhere in the world, you 'd send them straight into liquidation.