The Germans won the Champions League quarter-final first leg 2-0 at the Allianz Arena.
"It was a great advantage that we took the lead after 25 seconds, then the team worked very hard and showed great quality," Rummenigge told Sky Sport Italia.
"Juve are not to be underestimated, so we are going to Turin very concentrated, as we'll know they will try to give it their all.
"We are very happy, but there is no euphoria within the club. We know this was the first of two important games, but also that we have a team capable of scoring away from home."