Missing Roberto Firmino, Alisson, Mohamed Salah and Sadio Mané due to the Copa América and Africa Cup of Nations, Liverpool were hurt by defensive mistakes and Dortmund wasted no time in finding the net, courtesy of a close-range strike from Paco Alcacer after just three minutes.
Adam Lallana missed the last game with a slight knock, but should be in contention to continue to adapt in a new defensive midfield role that Klopp has deployed him in earlier this pre-season.
Klopp said: "Yasser played against one of the biggest talents in world football and did really well".
Brazilian duo Alisson Becker and Roberto Firmino, alongside Mohamed Salah are still absent on extended holidays after their global exploits in the African Cup of Nations and the Copa America.
I knew the penalty was going in as soon as he put the ball in his hands.
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He remained upbeat despite the defeat but blamed Dortmund's goals on a "lack of organisation".
It has been a good transfer window for Sevilla as they have secured solid signings in Luuk de Jong, Oliver Torres, and Fernando.
Harry Wilson drew Liverpool level after 35 minutes but Dortmund scored two quick-fire goals after the break.
Liverpool fans in U.S.A created an incredible atmosphere before Liverpool's pre-season friendly against Borussia Dortmund.
Needless to say, Liverpool didn't concede any more.
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En souffrance, le vainqueur sortant Geraint Thomas (derrière le maillot jaune Julian Alaphilippe ) lâche 36 secondes sur la ligne. Au point que le Français fait désormais figure de candidat crédible à la victoire finale, le 28 juillet, à Paris.
Brewster is a player who Sancho knows well from their time together during the youth setups with England.
An excessive heat warning had been declared in Northern Indiana, and after a baking hot day temperatures in South Bend were still touching 33C at kick-off.
It has been quite the year for Notre Dame Stadium.
The ground was just over half full, but those who had shelled out between $50 and $600 (£40-£480) for a ticket - and another $60 to park the auto - made plenty of noise throughout what one fan told me was "the biggest thing to hit town since Garth Brooks".
Liverpool resume their American tour by facing Sevilla in Boston before taking on Sporting CP in NY.
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