A routine post-game following Sunday’s Cardinals-49ers game took a drastic turn after tempers flared between Arizona running back James Conner and San Francisco safety Talanoa Hufanga.

The exchange took place as players and coaches walked off the field after the 49ers’ 35–16 win when, suddenly, a fiery exchange involving Conner and Hufanga broke out.

Fox cameras caught a shot of the players jawing back and forth before Conner mushes Hufanga in the face with his left hand. Conner then starts wagging his finger and talking to Hufanga, who responds in kind before the two are separated.

As of this publication, it’s unclear what led to the altercation.

While the fight may now overshadow the game’s aftermath, Sunday’s contest went down as a largely dominant showing by Hufanga’s Niners against Conner’s Cardinals.

Despite allowing 362 total yards, San Francisco (4–0), behind a big game from its offense, held Arizona in check en route to staying unbeaten heading into a Week 5 showdown with the Cowboys.