A boxing world champion's 7-year-old son punched his dad's opponent in the crotch

American boxer Willie Monroe Jr. got more than what he bargained for when an attempt to befriend his opponent’s 7-year-old son at a weigh-in was rewarded with a fist to the crotch.

Monroe Jr. is challenging for Billy Joe Saunders’s WBO world middleweight championship title at the Copper Box Arena in London on Saturday.

After weighing-in below the 160-pound (11 stone and 6 pounds) middleweight limit, Billy Joe Saunders flexed for the cameras at a press event on Friday.

Monroe Jr., meanwhile, ruffled the hair of Saunders’s young son, Stevie Saunders.

Saunders Jr. reacted by punching Monroe Jr. in the crotch. He also kicked him in the thigh before getting pulled away from the stage.

You can watch the bizarre incident unfold below.

Saunders Sr defended his son’s actions on Twitter. “My son has been taught [that] when a stranger puts their hands on them [they should] punch and run away in self defence.”

INCREDIBLE! @bjsaunders_ SON ATTACKS WILLIE MONROE JR AT WEIGH IN!!! ????#SaundersMonroeJr pic.twitter.com/R0TkCoOwqx
— BoxNation (@boxnationtv) September 15, 2017

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