Police had to separate players from both Manchester United and Liverpool as emotions spilled over into violence in the tunnel at Old Trafford.
The Premier League match was already the centre of everybody's attention as it pitted Luis Suarez against Patrice Evra for the first time since the former was banned for eight matches for racially abusing the latter during the reverse fixture in October.
Any hope that football might be the focus of the afternoon was dismissed even before a ball was kicked when Suarez refused the offer of Evra's hand during the traditional pre-match handshake.
And after a few more distractions - namely Suarez booting the ball direct at the dugout on the stroke of half-time - tempers boiled over as the two sides made their way back to the dressing room.
It was reported that Evra was intent of speaking with Suarez over the handshake snub, but found his path to the striker blocked by Liverpool defender Martin Skrtel.
That was the cue for a melee involving several members of both teams to become embroiled in a pushing and shoving match, which took up to five minutes for police to mediate.