The Spaniard has guided Bayern to back-to-back Bundesliga titles since joining them in the summer of 2013, but he recently acknowledged that Champions League success is a must if this season is to be considered a success.
Bayern face Barcelona in the first leg of their semi-final on Wednesday as they aim to make it to the final in Berlin, yet Effenberg feels Guardiola is having a hard time dealing with the demands at the Bavarians, citing his intensive coaching during matches as an example that the pressure is getting to him.
"I am not a fan of Guardiola's extreme coaching during games," Effenberg told Kicker.
"You have to trust your players, you have already prepared them for a match for days.
"On top of all that, Guardiola is also getting involved in discussions with the linesmen and fourth officials.
"That only further illustrates the immense pressure he is under."
Effenberg then went on to criticise Guardiola's possession-based style of play and stressed that the ex-Barcelona coach's philosophy was exposed by Real Madrid last term.
"Bayern always have 65 to 70 per cent possession and want to be an offensive force.
"But things went wrong for them in the semi-finals against Madrid last season. Carlo Ancelotti performed a tactical masterclass and exposed Guardiola."
Former Netherlands international Willem van Hanegem is another who feels Guardiola is struggling and questioned, in particular, his decision to bring on Arjen Robben in last week's DFB-Pokal semi-final against Borussia Dortmund.
Robben lasted just 16 minutes into a comeback from an abdominal injury before limping off with a calf problem. He was later ruled out for the rest of the season, depriving Bayern of their most creative player at a key stage of the season.
Van Hanegem wrote in his Algemeen Dagblad column: "I think Barcelona are not unhappy with the absence of Arjen Robben. He is the kind of player that can create something when Bayern are stuck.
"Therefore I don't understand why Robben played against Borussia Dortmund last week. You always know that there is a high risk with Robben and that he can suffer muscular problems. But it seems to me that Guardiola has been a bit stressed the last couple of weeks
"I think that Barcelona and Real Madrid will reach the final. I understand that people would rather see two teams from a different country, but I can live with this final. The two best teams should be up there and at this moment they are Real and Barca."