I'm posting this thread because I just watched the Fulham/Millwall match from April 2018 (90 Minutes). As an American I've only heard rumors of how "feisty" Millwall fans can be. Man, the atmosphere in that game was crazy electric. Loudest fans I've heard in a soccer/football match ever.
Hopefully they won't get relegated so I'll be able to watch them again next season.
I was there and for us, we were loud too.... they definitely had an advantage with the fans behind them like that. It was all them first half!