Antic says fellow Serb Ivanovic can use his considerable physical presence to put the frighteners on Barcelona's sometimes vulnerable rearguard.
Antic told the Sunday Mirror: "Not often, but sometimes Barca wobble. Where I see a big chance for Chelsea is at set-pieces. Barca do have problems in their defence at times, and Chelsea just have to be positive from the very start.
"Ivanovic is a threat that's very hard to deal with."