The match itself defied predictions of an easy Barca victory in the first leg. It appears that La Blaugrana has to prepare themselves mentally for the second leg of the UCL and El Clasico against Real Madrid.
Chelsea FC had the advantage of the first leg being played in their home country. La Blauigrana did not have the force and the tenacity to play.
Andres Iniesta, who is a Barca midfielder, recognized that there was a lack of a "killer instinct" in the match. What happened was that La Blaugrana underestimated the Blues which is something that should not be done.
Dani Alves did the unthinkable when he said that Chelsea "lacked the courage" and "played with fear." The declarations by Alves emboldened Chelsea to show La Blaugrana that they can be very tough when the situation arises.
The lesson that La Blaugrana should learn is a basic one. Barca (and other teams) should never underestimate or belittle the opposing team.
The results can come back to haunt the club whose member underestimated the opposing one.