Borussia Dortmund cruised to a 3-0 victory over FC Copenhagen in their Champions League Group G opener on Tuesday with the Germans playing in front of a rare capacity 81,000 crowd for a European match.
Captain Marco Reus rifled in for the lead in the 35th minute before Raphael Guerreiro added another just before the break and Jude Bellingham made it 3-0 in the 83rd with the hosts powered on by the famed 'Yellow Wall' with 25,000 standing fans.
Governing body UEFA has allowed standings fans in some matches in Europe this season, boosting capacity for some teams.
"We've got some tough trips to come. Tonight was a massive game and people maybe don't realise how important the first game is," scorer Bellingham said.
"The key for us is to try and be as consistent as possible, work hard to stay in the competitions as long as possible. If we can stay on this path I think we'll be alright," he said.
Dortmund, missing several players through injury including goalkeeper Gregor Kobel, Mo Dahoud and Jamie Bynoe-Gittens, were almost caught by surprise after 20 seconds with Copenhagen captain Zeca's shot hitting the post.
They gradually took control and forward Anthony Modeste, who at 34 became the oldest Dortmund player to make his Champions League debut, fired over the bar after good work from Julian Brandt in the ninth minute.
The Danes quickly fell back again and Dortmund should have scored another well before Bellingham completed a quick transition in the 83rd following another assist from Reyna.