Arghus Soares Bordignon says there is nothing to fear as Jose Mourinho's side travel to Slovenia to play Maribor in the Champions League.
Two weeks ago, the Maribor defender Arghus was on the bench when the Blues beat Maribor 6-0 at Stamford Bridge.
And, the 26-year-old Brazilian is convinced they can upset Chelsea at home [Stadion Ljudski vrt] despite losing to Domzale at home on Friday.
"Chelsea are a big club, probably the biggest to ever come to our stadium," Arghus said on uefa.com.
"But I trust my colleagues, we believe in ourselves and we know that we can play against any team in the world.
"Of course Chelsea are big favourites, but they will have to beat our defence first.
"Yes, they are quick with a lot of creativity in attack. Everybody knows Chelsea - we watch them every week - so we know that they don't have any weaknesses.
"But at the same time we are not afraid of anyone."