Barca were reduced to 10 men when Frenkie De Jong received a second yellow card. Koeman was then sent from the touchline for debating a late decision with the fourth official.
“I was sent off for telling the fourth official that there was a second ball on the pitch and the game should be stopped,” the 58-year-old added.
“Everyone saw that except the referee. In this country, they send you off for nothing …They say [it’s for] ‘attitude, attitude,’ … It is better we leave it there because it’s not my problem.”
On Wednesday, Koeman refused to answer questions from the press and instead delivered a sensational pre-prepared statement defending the job he has done with the Blaugrana.