Pulisic efforts then set up Jacob Bruun Larsen to score Dortmund's final goal late on. But the "Man of the Match" award Sunday was sponsored by Heineken and, due to the legal drinking age in the USA being 21, Pulisic could not receive it, according to Goal.com.
While Pulisic took part in a post-match interview, a young fan ran onto the pitch and approached the 19-year-old American.
And it is certainly warranted from the 25-year-old, despite a series of lacklustre displays during meaningless pre-season friendlies this summer.
Liverpool came close to doubling their lead but Sheyi Ojo was denied by the crossbar.
"I like Christian, I've known him since he was a kid".
Watch: Christian Pulisic scores twice, sets up another vs. Liverpool
"He wants to be, I'm sure, the best Christian Pulisic he can be. I'm fine with him, 100 per cent".
While a third supporter questioned if he was still having health issues.
Of course, results matter for little at this point even if it feels better to win.
But against Liverpool, the German side were poor in front of goal with no one able to put much pressure on the Reds' defence when their wide players had broken through - despite being saved by Pulisic after his arrival.
His misery was compounded with the signing of highly rated Roma goalkeeper Alisson, who will go into the new Premier League season as Liverpool's goalkeeper.
Klopp publically backed Karius to remain between the sticks despite his now infamous errors in the Champions League final, and the club briefly gave up on signing Alisson when Real Madrid made an enquiry.More news: U.S. officials still in the dark on what Trump discussed with Putin