The former West Germany international was blown away by the Bavarians' performance against the Blaugrana, but acknowledged the advantage of facing an unfit Lionel Messi
The Bavarians went into the game at the Allianz Arena as slight favourites, but few pundits foresaw Jupp Heynckes' men sweeping the Catalans aside as they did, with a Thomas Muller double and a goal apiece from Mario Gomez and Arjen Robben.
Rummenigge admits he was bowled over by the standard of his side's display, telling Sky Deutschland: "We won 4-0 against the best team in the world. That is like a dream here tonight.
"We played beautifully. We did not give our opponents any chances. I do not think Barca ever had a game where they had so few chances.“
The legendary striker was full of praise for two-goal hero Muller, but he was keen to acknowledge that Blaugrana star Lionel Messi had clearly not recovered from his recent hamstring trouble.
"Thomas Muller had a fantastic match," Rummenigge enthused. "But I still think Messi is the number one. I don't think he was completely fit."