A Millwall fan in a baseball cap and grey jumper marched 30 yards along the front of the Dockers Stand unopposed by stewards to hurl expletives and hand gestures toward a boisterous corner of Leicester City's away support at The Den.
He strutted back to his mates, laughing and boasting of his exploits. By the time the final whistle blew and Millwall had sealed an historic FA Cup fifth-round victory against the Premier League champions, they were joined by thousands of others on the pitch.
That corner where the Dockers Stand meets the away north stand can be particularly hostile.