When USWNT players came out for warmups with their shirts inside out, revealing an empty crest with four stars above it, it became a fashion statement met with overwhelming fan approval.

Last week, an indelible protest by the U.S. women’s national team against the U.S. Soccer Federation turned into a viral business opportunity—and showed exactly how rabid the fan base for the USWNT really is.

BreakingT is a company that makes moment-driven sports apparel, the kind that can jump on fan interest in real time to sell T-shirts and sweatshirts immediately after games. The company got the license for the USWNT Players Association ahead of World Cup 2019, and it had success selling shirts during the tournament like Rapinoe-Bird 2020, a nod to Megan Rapinoe and her partner, WNBA star Sue Bird. (BreakingT also has the license for the WNBA players union.)

But what happened last week during the SheBelieves Cup put those World Cup sales figures to shame.

It started with Christen Press’s bending golazo against England. BreakingT immediately put out a shirt bearing the likeness of Press and the call from ESPN broadcast Sebastian Salazar: “CHRISTEN PRESS, WHAT HAVE YOU DONE?”

“That sold really, really well,” said BreakingT’s director of marketing, Dom Bonvissuto. “And it just continued to shine a light on the fact that women’s soccer and its fans are super-passionate and exactly the right fan base to hit with this model. Then on Wednesday night we saw that the women walked out with their warmups inside out. And we were obviously struck immediately by the empty shield with the four stars. That’s a shirty thing. We need to get going.”

The USWNT’s protest was elegant in its simplicity. Two days earlier, new filings in the USWNT players’ gender-discrimination suit against U.S. Soccer had been released in which the federation argued that women’s players inherently had less skill, ability and responsibility than men’s players, which is why women were paid less than men.

The legal strategy might have been useful in a court of law, but it was offensive and objectionable on a massive scale. Several U.S. Soccer sponsors—Coca-Cola, Budweiser, Deloitte, Volkswagen—issued strongly worded statements excoriating the federation.

Meanwhile, the USWNT spoke with action. On game day, the players came up with a plan. Wearing their pregame warmups inside out made invisible the U.S. Soccer badge and left only the badge’s outline and the four stars above it, representing the team’s four World Cup victories. It was the perfect symbolism, a way to show the abject emptiness of the U.S. Soccer Federation while still honoring the players who have led the U.S. to its greatest soccer triumphs.

The U.S. players only reinforced that point by having every single player on the team pose unsmiling in those shirts for the pregame photo that usually just includes the starting 11 players.

BreakingT had a design for a T-shirt ready before the game even started and got it approved by Becca Roux, the executive director of the USWNTPA. Bonvissuto (full disclosure: He used to work as an SI.com editor) hit send on the first tweet announcing the sale of the “4 Stars Only” T-shirt (price: $28) at 10:17 p.m. ET on Wednesday, within minutes of the final whistle.

“And it hit like crazy,” he said.

Goosed along by tweets from Alex Morgan, Ashlyn Harris and Allie Long, the sales were remarkable. Even though the shirts were available for only one hour and 43 minutes on Wednesday, that day was the best-selling day for direct-to-consumer sales in BreakingT’s history. On Thursday came another record.

“4 Stars Only” sold far more online than anything the company has ever produced, including all of the World Cup 2019 shirts and shirts commemorating the titles of the Washington Nationals and Kansas City Chiefs. When it came to “4 Stars Only,” Bonvissuto said, “We sold more than 5,000 units in the first 24 hours.”

The USWNT players receive a portion of the proceeds, of course, but even on Wednesday night they anticipated what they might want to do with those.

“We've already had conversations about where some of the proceeds from this could go, especially with the women's national team games being canceled in April,” Roux said. “Is there a way for us to funnel money to those independent-contractor employees who would have otherwise received work for those two games? That was something the players brought up on Wednesday night before we knew how successful it would be after the game.”

One of the challenges of having a T-shirt company that has to work fast off breaking news is getting the various clearances to do so, including from the legal side of things. BreakingT did another shirt on Julie Ertz’s late game-winning goal against Spain (ERTZ SO GOOD). When it was pointed out on Twitter that the drawing of Ertz looked just like a shot taken by photographer Ashley Intile, the company ended up doing a royalty agreement with Intile.

The success of the USWNT players’ own licensing ventures also shows that their ability to generate revenue goes far beyond what the federation has said and done with the team in the past. As Roux put it, “The players thought there was more in the market that wasn’t being monetized. There was value being left on the table, while at the same time the federation was using an argument of revenue generation against them.”

“4 Stars Only” is just the latest evidence. It won’t be the last.