Borussia Dortmund manager Jurgen Klopp is held in high regard by most thanks to his affable nature and good sense of humour, but the German let his usual jolly exterior slip dramatically on Wednesday.
Klopp established himself as one of the most popular coaches in Europe last season thanks to his zany dealings with the press, but showed a different side during Borussia Dortmund's defeat to Napoli.
The BVB boss was incensed by Napoli's opening goal of the encounter, which finished 2-1 to the Serie A side, and made his frustration clearly known to the cowering fourth official.
Klopp's face became contorted with rage as he harangued the man on the touchline, and soon found himself sent to the stands after allowing his frustration to boil over in typically bonkers.
Watch Jurgen Klopp lose it in the video above.