The summer signing from Vitesse Arnhem was handed a starting place by Sir Alex Ferguson as the Red Devils overcame a 2-0 deficit to win 3-2 at Old Trafford.
And, despite giving a mixed performance, the defender was pleased to have made the step up to Europe's premier cup competition.
Speaking to reporters after the match, Buttner said: “[Champions League] is a higher level. It's my first game, I want to play high-level football.”
Buttner has been touted as a potential threat to Patrice Evra’s starting position at the club since arriving from the Netherlands, but the 23-year-old insists he has nothing but respect for his team-mate.
“Patrice is also good,” he said. “If he plays, it's OK. I look to him and how he plays, and I learn from that.
“On the training ground, we speak a lot. We are in the same position, we are left-backs.”