Beier struck 20 minutes from time as Dortmund edged Stuttgart in a tight contest, giving Niko Kovac's side another valuable three points before the international break.
Kovac was delighted to see Beier make an immediate impact after being left out of Jurgen Klopp's extended Germany squad, despite 44 players being selected for the national team's four upcoming matches.
"Life writes the most beautiful stories," Kovac said after the game. "Maxi Beier isn't with the national team, but today he was the one who scored.
"I'm thrilled for him, and it ultimately shows that we have a great squad and a great player in Maxi, and that he has rewarded himself with this goal today. Now, he can take a few days off and work from home."
Beier's decisive moment came after a well-timed cross from substitute Jobe Bellingham, leaving the forward with the simple task of finishing the move.
"For a forward, nothing's better than only having to say thank you," Beier said.
The Dortmund striker also highlighted the importance of keeping Stuttgart out at the other end.
"First and foremost, we had to keep a clean sheet here at Stuttgart. We did so emphatically throughout the 90 minutes," he added.
Kovac admitted the match was different from some of the previous meetings between the two sides but was pleased that Dortmund came away with the result.
"From both sides, it was an intense game that did not have quite as much as one knew from past encounters between Dortmund and Stuttgart," he said.
"It is a statement win to do it here."
Dortmund will return to Bundesliga action against SV Werder Bremen on Friday, 9 October, when they host the match at Signal Iduna Park.
