City supporters have long booed the competition's anthem as well as leaving the stadium looking sparse for weeknight matches.
But Guardiola has used a promotional campaign from City to urge supporters to embrace the competition.
"Every Champions League game is special," he said. "I cannot choose [just] one. Every single game in the Champions League is amazing.
"I was not here for what happened but they must forget what happened in the past," he said. "We have to be so proud to play in this competition.
"I am going to work until the last moment to convince the people to come here to join us to see the Champions League games.
"Our players deserve the stadium completely full."