The 18-year-old received extended medical attention and was stretchered off the pitch on 80 minutes after the French defender hacked him - an offence that drew a straight red card.
Joris Gnagnon was red-carded for a trip on Yasser Larouci in the 76th minute, seconds after what Sevilla players considered a non-call tackle by Dejan Lovren.
Sevilla manager Julen Lopetegui said he checked with Klopp after the match and was relieved to hear Larouci was not seriously injured.
"Gnagnon was very anxious". I feel like he is at the right club, he is developing and he is still so young.
With temperatures in the mid-90s, a crowd of 35,654 filled nearly every seat in the ballpark, a lot of them dressed in red to support Liverpool.
To deal with the heat, the game was stopped once each half to give the players a chance to hydrate; the Fenway grounds crew also came out with hoses to wet down the infield, and sprinklers took care of the outfield.
Trailer for 'Top Gun: Maverick' starring Tom Cruise (and his stunts)
And those aerial shots? " Top Gun: Maverick " is anticipated to cruise into theaters in 2020. Her character will reportedly own a local bar in the film.
With Sadio Mane, Roberto Firmino and Mohamed Salah all given extra time off after global duty, Brewster was given his chance in the second half, coming on for Divock Origi after an hour. Sevilla, however, found the back of the net in the 89th minute to go up by what would be final score of 2-1.
Divock Origi levelled matters in the 44th minute when he buried his opportunity after a header deflected to him.
"We lost 2-1. I hate that fact", Klopp said.
The stands were packed at Notre Dame Stadium - there hasn't been that much red in the crowd since the Georgia game in 2017. "We wanted hard challenges, that's why we chose these teams as opponents and so now we have to fight".
The team, which, of course, is owned by Red Sox owner John Henry, played in front of a majority of Liverpool fans on a hot day in Boston.
One player who has started both games for Dortmund is Paco Alcacer and he opened the scoring with his second goal in two games after three minutes, following good determined play from Giovanni Reyna.