He's lucky he didn't get a kick from Eden Hazard.
The Mirror report that Mourinho said of the incident, where the ball boy was slow to return the ball for a Chelsea throw-in, 'I told him (the ball boy) not to do that because he runs the risk of one of my players to punch him or to lose his temper.'
He continues:
'I went there to stop Azpilicueta because I know that Azpi is an emotional guy.
'I was afraid of Azpi… to push the kid or to create a situation so I went there just to stop my player, not anything else. And the kid knows because it was what I told him.'
Jump to 1.40 here to see him talk about it.
https://www.youtube.com/watch?v=zB3JUpr8rOA