Jurgen Klopp expressed regret after reacting angrily to a Swansea supporter during Liverpool's shock 1-0 defeat at the Liberty Stadium.
Alfie Mawson swept home Swansea's 40th-minute winner following a poor headed clearance from Liverpool's £75 million record signing Virgil van Dijk.
Liverpool almost rescued a point when Roberto Firmino's header struck a post in stoppage time, but it was a miserable night for manager Klopp, who was involved in an angry exchange of words with a Swansea fan in the second half.
"He was shouting at me all the time and I reacted once," Klopp said. "I must remind myself I'm a human being and not just a professional manager who takes that all the time.
"They can say whatever they want, at one point I turned to him and said, 'Please!'
"It was only one moment when I had enough, it wasn't to do with the fact we were 1-0 down. I'm sure I am not the first manager who has had a problem with him there, he must be a season-ticket holder.
"It was my fault as well. I should not react, but I didn't say anything bad. I just showed I wasn't happy about what he was saying"