After being sent off for protesting, Guardiola felt that Barcelona should have won a penalty but he should not have reacted the way he did.
The Blaugrana coach was incensed when Lionel Messi was booked after colliding with a defender as the referee felt he had simulated a foul in search of a spot-kick.
After protesting vociferously to the officials nearest to the Barca bench, Guardiola was sent to the stands for his troubles and admits he should not have reacted the way he did.
"I should not have behaved like I did, I should have controlled myself. But I still believe that the decision not to give a penalty was scandalous," AS quoted him as saying.
"We were two goals ahead and a third goal then would have allowed us to relax. The referee knew it was a penalty. Even a blind person could see it was a penalty."
Despite securing a four-goal victory, Guardiola stated that he wants Barcelona to score again in the Allianz Arena next week in order to ensure themselves of a place in the semi-final.
"We need to score a goal in Germany with respect to the fact that in their team they have great players that have won world and European honours," he continued.
"We spoke in the changing room and I said that Bayern never give up and that we should go for more goals.
"We were good at turning defence into attack."
With the Champions League victory under the belt, Guardiola was already focused on the weekend encounter against Recreativo de Huelva in Camp Nou.
"Now our thoughts are on Recreativo and to decide how we take a break because Madrid are pressing and I doubt they will lose their rhythm because they are strong," he added.
"The key is to not think about defending the six point lead, but instead to think about adding three more."
Lucas Brown, Goal.com