Lilian Thuram fears Rangers' spirit will 'drive Barcelona mad' in Wednesday's UEFA Champions League clash at the Camp Nou, which is live on Sky Sports Xtra.
Rangers frustrated the Spanish giants at Ibrox a fortnight ago when they earned a battling 0-0 draw.
And Thurham is expecting a repeat performance in the top-of-the-table Group E clash, with both sides aware that three points would book a place in the last 16 of the Champions League.
"Rangers showed at Ibrox they are strong," Thuram said in the Daily Record.
"They just about drive you mad because of their pressure and the fact they never seem to give in.
"Like Frank Rijkaard (Barca manager) says, you should never underestimate any rival and must respect them - Rangers deserve our respect.
"They were determined not to lose in Glasgow and fought for it in their special way.
"You have to give them credit, though of course we want to beat them tomorrow."