The striker confirmed BVB's 2-0 win over Bayern Munich in the DFL-Supercup with a second-half header, which he celebrated by pulling on a Spiderman superhero mask over his face.
"We're delighted to have made this start to the season and to be in such rhythm," said the striker, according to the Bundesliga's official website.
"The Spiderman mask was for my son. I promised him I'd do it for his third birthday and I wanted to score for him. I think Kevin Grosskreutz has the mask now."
Dortmund begin their Bundesliga campaign when they face Bayer Leverkusen next weekend.