Footballers be warned: Never forget there are cameras everywhere at matches these days.
Unfortunately, PSV Eindhoven striker Jeremain Lens did not remember the old adage and is now facing an investigation by the Dutch FA (KNVB).
The Holland international was involved in an altercation with Feyenoord defender Joris Mathijsen toward the end of the Eredivisie clash on Sunday.
But the 25-year-old prowled the tunnel area after the game waiting for his opponent to leave the field after celebrating the Rotterdam club's 2-1 victory.
Lens approached Mathijsen as he headed to the dressing room and grabbed him by the shirt.
Players and officials attempted to separate the two players before a mass brawl broke out, all witnessed by cameras inside the tunnel area at De Kuip.
Lens told reporters after the game that he was sorry for the incident and should not have waited for Mathijsen in the tunnel after the match.
Feyenoord coach Ronald Koeman had seen his side come from behind in the match to cut the deficit on league leaders PSV to three points.
Ajax are second in the Eredivisie table, just two points behind Dick Advocaat's Eindhoven side.
Lens and Mathijsen are expected to be named in the same squad when Holland play host to Estonia in World Cup Qualifying Group D on Mar. 22.