Barcelona coach Pep Guardiola is worried by the vast experience of Michael Essien and other Chelsea stars ahead of their Uefa Champions League semi-final clash next week.
Chelsea are seeking revenge against the holders for the controversial refereeing decisions from Norwegian centre referee Tom Henning Ovrebo that denied them a place in the final in 2009.
However ahead of the crucial clash next week, Guardiola fears Essien who has close to eight seasons of Uefa Champions League football remain a big threat to his side's title ambitions.
"Forget about whether they have a good or bad year. This will be a two-game knockout round and they are capable of anything. I am talking about Terry, Essien, Cech, Lampard, Drogba, Torres, etc."
"Chelsea has seven, eight, nine players who have been playing Champions League for centuries.
"And they know this job like nobody else does. Like nobody else."
Essien did not play a part in Chelsea's quarter-final progress at the expense of Portuguese side Benfica.