The roughly 400 New York Red Bulls fans who made the trek to PPL Park on Saturday were herded like cattle into the visitors' section in the corner of the stadium opposite the Union's bench.
Once they were in, they were there to stay - surrounded and confined in that area by security for the duration of the Union's 2-1 win in Major League Soccer.
They had their own concession stands, their own restrooms, their own smoking area.
"These fans hate each other," noted one Union security guard, who helped successfully keep the Red Bulls' fans confined and Union fans at bay.
It was fan appreciation night at PPL - Union fan appreciation night. The organization wasn't going to let the final home game of its inaugural season be spoiled by any Red Bulls hooligans.
For the Union, the tension in the stands is a good thing. After a convincing win, the team said it would like nothing more than to sustain a heated and legitimate rivalry with one of the best sides in MLS.
"We think we can compete with any team," Union coach Peter Nowak said. "The tag of an expansion team is long gone."
The Union (8-14-7) took a 2-0 lead into halftime, but the Red Bulls (14-9-6) came out firing in the second half.
Danleigh Borman's goal in the 48th minute brought the Red Bulls to within a goal.
The Union had taken an early lead when midfielder Fred netted a goal in the eighth minute. The Union continued to control the run of play throughout the first half. A goal by Michael Orozco Fiscal put the team up, 2-0, in the 28th minute.
The Union finished their home schedule with a 6-3-6 record.
That the night went off without a hitch was a sign that the organization's battle against crowd disruptions was a success.
As for the Union's battle on the field with the first-place team in the Eastern Conference, that went pretty smoothly, too.
"It's motivating to have a rivalry against them," Fiscal said. "We have to go out there and show our fans and show ourselves that we can compete with anyone."