The Dutchman received a red card in the last minutes of the match after he objected to the referee’s showing of a yellow card to Barcelona captain Sergio Busquets.
The referee issued the yellow card to the Spanish midfielder after kicking a second ball on the field towards the Cadiz player, who was in possession of the original ball for the match.
After the match, which was the third in a row without a win for Barcelona, Koeman said: “They did not fire me because of nervousness, but because I told the referee that there was a second ball on the field and he had to stop the match.”
And the former Barcelona defender added in his interview with the club’s channel, “In this country, they expel you for no reason! I said why, and he replied: Behaviour, behavior.”
Barcelonas new stumble made it eighth in the Spanish league standings, with only 9 points after playing 5 games.
Barcelona will host Levante on Saturday in the seventh round of the league.
Then he heads to Portugal to face Benfica in the second round of the group stage of the Champions League.
After that, a fiery confrontation awaits him in the capital against Atletico Madrid, the champions of the league.