Pep Guardiola was fuming on the sidelines as Milner escaped punishment for a second yellow card after a poor challenge on Bernardo Silva.
Milner was withdrawn shortly after and Klopp says he was always planning on taking off the veteran Englishman.
"I heard that, but I didn't see it, I was too far away but I saw the reaction from the City bench," said Klopp on Milner escaping a sending off after the 2-2 draw.
"We planned to take Milly off because of the yellow card from the first half.
"Our reaction in the second half was us. Second half was brave, aggressive, full of determination, we were ready to play the small spaces, play the extra pass and use the width.
"It is a really good lesson for us not that I needed it, but at least when you get something like that first half you need to show a reaction and the boys did show this reaction, they were absolutely great.
"Even with two good halves there are times we do not win against City but the first half was probably the worst we played against them."
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