Chelsea's defensive strategy has been extremely effective in first leg Champions League semi-final against F.C. Barcelona. Di Matteo's approach has been better than Guardiola's, but Chelsea could have been easily defeated if Barca would have taken advantage of their goal chances. Unlucky day for Barca's forwards.
But, 90 minutes in Camp Nou won't be the same and it will be almost impossible that Barca wont score in their stadium. I think that match is going to be eternal for this ultra-defensive Chelsea and sooner or later Barcelona will score. Chelsea's sources won't be enough to beat Guardiola's team and reach the final. They've been lucky in the 1st leg, but Barca won't fail at home.