Klopp says he deserved to be booked by Polish referee Szymon Marciniak in Liverpool's 1-0 first-leg loss.
An angry Klopp was cautioned by Marciniak in the second half in the Spanish capital, but the German insists it wasn't for any specific words in the official's direction.
“I deserved it. I was just shouting in the direction, no bad words, I was not swearing," Klopp told his post-match press conference.
"I was just unhappy with the overall performance and in that moment it finally came out and the ref didn't like it too much. I can take that, I deserved the yellow card."