And America's Sweetheart doubled the excitement among the crowd, scoring the winning goal with minutes remaining - potentially passing his audition for a Liverpool move.
Karius has been a subject of ridicule from many fans after two glaring errors against Real Madrid in Liverpool's 3-1 Champions League final defeat.
It was a Dortmund substitute, Christian Pulisic, who restored parity from the penalty spot after the winger had been brought down in the box after 66 minutes.
The impressive Curtis Jones was among eight Liverpool withdrawals at the break, with Naby Keita introduced, while Dortmund also made wholesale changes for the second half.
Only four minutes had elapsed when Karius rushed out his goal to produce a poor clearance straight at Borussia Dortmund forward Maximilian Philipp.
The midfielder played 45 minutes here, displaying some nice touches in attacking areas, and is targeting a place against West Ham on the opening day.
Jurgen Klopp gives details on Joel Matip injury
Clear cut chances were few and far between in the opening 15 minutes, despite both sides playing at a good tempo early on. Obviously we can not say more about this now, but that's of course the most negative thing about the day.
U.S. gunman arrested after Hollywood hostage situation at Trader Joe’s store
Around 1:30 p.m., police spotted the suspect driving his grandmother's vehicle in the Hollywood area and a pursuit began. CNN spoke to employees at nearby Jersey Mikes and What the Fish, both stores are on lockdown and no one was injured.
Trader Joe's Employee Helps Hostages Escape Gunman; 1 Dead In Los Angeles
She was pronounced dead at the scene, according to LAPD officials, who said the woman had been " struck by gunfire ". Officials with Trader Joe's issued a statement late Saturday praising police and vowing to help its employees heal.
James Milner took the armband for Liverpool and nearly doubled his side's lead 11 minutes after the restart when he curled an effort towards the top corner, only to see it fly narrowly over the crossbar with the goalkeeper beaten.
Milner's cross was then headed wide by Dominic Solanke as Liverpool, who had been unbeaten in pre-season, continued to push for a decisive second goal.
As Liverpool went all out to grab an equaliser, Jacob Larsen added a third in injury time.
Andrew Robertson - 7: Never really exerted himself, his cross to set up Van Dijk's towering header for the first goal was perfection, holding himself back waiting for the season proper to start.
For Dortmund's late third goal, he was again unconvincing.