Virgil van Dijk's header had given the Reds a first half lead in a match where they were in control for so long, before Pulisic's second-half intervention - two goals and an assist - turned the tide.
Story of the match
Two favourites that were back in pre-season action were Andy Robertson and Van Dijk, linking up to produce the opener as a corner was cut-back to Robertson, whose cross was powered in by the Dutchman.
Keita looked slick from the get-go, one particularly dazzling step-over sending his man back across the Pacific, Liverpool players straining to get to his ball into the six-yard box.
However, Pulisic entering the game at half-time would prove to be the key factor in the result, the 19-year-old winning and converting a penalty to level the scores just after the hour mark.
He rattled in a second a minute before time, Liverpool left wondering how they'd lost the game as Pulisic struck into the corner to conclude a counter-attack, while there was still time for a third Dortmund goal as Pulisic's shot was spilt by Loris Karius into the path of Jacob Bruun Larsen to tap-in.
Pulisic impresses Klopp once more
Christian Pulisic was handed his Dortmund debut a few months after Jurgen Klopp left, but that hasn't left the German in any doubt about the talent of the American - liked by Liverpool's owners for his marketing potential in the States as well as his talent.
Asked about Pulisic prior to the game, Klopp respectfully reminded journalists that the player has a contract to uphold, whilst doing little to hide his admiration of the winger.
Only failing to be awarded Man of the Match because sponsors Heineken can't give alcohol to an 19-year-old in America, Pulisic's performance will only have increased Klopp's admiration, Liverpool's defence left on strings by the wonderkid in the last 30 minutes.
One Liverpool defender heads in, one heads off
Virgil van Dijk's powerful header in the first half was welcomed by Klopp, but his centre-back partner Joel Matip limping off wasn't.
Matip was side-lined during the run-in last season through a thigh injury, Klopp insisting it's not a reoccurrence of that problem but unable to confirm Matip will be fit for the Reds' season opener against West Ham.
Karius in the headlines again for the wrong reasons
Loris Karius has had a tough time of it since 'that' Champions League final, another glaring error coming his way in this game.
However, his flapping at Pulisic's strike in stoppage time was indicative of his current level of confidence, Larsen profiting and Karius left pondering, offering the following message on Instagram some hours later.
"To those who take joy in seeing other people fail or suffer, I feel for you. Whatever it is that's happening to you in your life to hold this much anger and hate, I pray that it passes and good things come to you."
Pulisic was the obvious star of the game, but another impressive showing from Naby Keita will further excite Liverpool fans as to what he could do in the coming season.