When Mou is involved, chances are more than not, that you'll get a boring grindfest of a match.
He's simply just too conservative of a coach, even with a lot of good players. He'd rather not lose than win, and when that's your mentality, you'll get plenty of snoozers.
Arsenal is always truly dire when they meet Chelsea, so its no wonder Mourinho feel confident doing it against the chokers in red and white. Awful stuff in the final third.