Ronaldinho believes Chelsea will rue the day they let Eidur Gudjohnsen quit the capital to sign for Barcelona.
The Icelandic hit-man ended a six-year association with the Premiership champions in the summer when Jose Mourinho allowed him to join Barcelona in a £8 million deal.
Gudjohnsen has already endeared himself to the Catalan faithful having marked his competitive debut with a winning strike against Celta Vigo and it would appear his popularity extends to his team-mates.
In what seemed to be an almost inevitable twist of fate, Chelsea were drawn with Barcelona in the opening stages of he UEFA Champions League and Ronaldinho is confident his new team-mate will be able to provide crucial insight.
"He is a great player and he showed that when he played in England," said the Brazilian.
"He has already shown with Barcelona that he is a very skilful guy.
"He will prove to be very important for us this season and he will also help us against Chelsea.
"I never get tired of playing Chelsea. All the top players and the top teams want to play against the best teams.
"Chelsea are one of the biggest clubs in the world. It is always a thrill to play against them and I am happy we are meeting at this stage in the Champions League."