"There was a sea of Patriots fans right behind our bench," Belichick said Monday via the Boston Globe. "I don't think I've ever quite seen that before. They were just kind of all in the same spot, it was almost like a college game in a neutral site where one side of the field is one team and the other side is the other team."
Belichick noted that he heard the crowd cheer a few times and thought "Uh oh, what happened?" and it was actually Patriots fans cheering for a good New England play.
This is what happens when a conference rival has a rare road game in a stadium that has struggled at times to sell tickets. It doesn't hurt that there are a ton of Boston transplants on the West Coast. Belichick was smart to set up shop in San Diego for a week, just like many of those Patriots fans were smart enough to leave Boston and set up shop permanently on the West Coast.