The 66-year-old led Real to their seventh European crown in his first season at the Bernabeu, with a 1-0 final win over Juventus 13 years ago, but has not returned to the continent's top club competition since.
He avoided a potential banana-skin by steering Bayern past FC Zurich in the play-offs last month, and opens his Group A campaign with a trip to Spanish side Villarreal on Wednesday.
"I can't get worked up about it. I've experienced everything in European competition as a player and a coach," Heynckes, a World Cup and European championship winner as a player with West Germany, told reporters at the Madrigal on Tuesday.
"My approach is professional and unemotional.
"The games against Zurich were definitely an appetiser."
Heynckes returned for a third stint as Bayern coach in July and has to shoulder the added burden of expectation with this year's Champions League final being played at Bayern's Allianz Arena next May.
"We know we have been picked in a very difficult group with teams who are currently the best in the world," he told reporters.
"This is the Champions League and if you want to achieve something you have to fight hard. We have absolute belief in our possibilities and playing against Bayern is a massive motivation."
