Given that it was the first leg of a semi-final, the stakes were high so you can imagine Simeone's reaction to seeing right-back Sime Vrsaljko sent off for two bookable offences with a little over 10 minutes gone.
Furious, the Argentine let rip at the fourth official and the referee, before being promptly sent to the stands, much to the amusement of the Arsenal fans.
The watching faithful waved 'Cholo' from the field, barely able to hide their amusement.
Check out their reaction for yourselves below:
April 26, 2018