U.S. women’s stars Tobin Heath and Christen Press shirts have been selling like hotcakes since they both signed for Manchester United back in September. They've been bought up so quickly, in fact, they outsold any men’s shirt within the first three days of their release.Heath and Press, both two-time World Cup champions, signed for United in September on one-year deals from Portland Thorns and Utah Royals respectively. The signings were the latest in a long line of U.S. players who’ve switched life in the States for England’s Women’s Super League.

This transfer window has seen the likes of Sam Mewis and Rose Lavelle join Manchester City, while superstar Alex Morgan has linked up with Spurs. The WSL has been on an upward trajectory for some years now, but this summer felt like a seminal moment for the league.

Current champions Chelsea even broke the world transfer record during the off-season, capturing the signature of Denmark captain Pernille Harder for a reported €300,000.

Heath and Press shirts fly off the shelve

The shirt sales are even more impressive when you take into account United’s current men’s squad: David de Gea, Paul Pogba, Bruno Fernandes, Marcus Rashford. Some of football’s biggest names currently ply their trade for the Red Devils, demonstrating just what a feat it is to outsell shirts with any of their names on.

Women’s football, or soccer, is huge in the U.S., with their national team having been at the pinnacle of the sport for some time. Of the eight World Cups that have taken place since the inaugural tournament in 1991, the USWNT have won half of them, including the last two.

That dominance has ascended female players in America to a level of international stardom seldom seen in the women’s game before. Players like Megan Rapinoe are household names, and have used their platforms to shine a light on pressing societal issues, such as systemic inequality and political corruption.

Heath, a technically-gifted attacking midfielder, and Press, an athletic forward, have evidently whipped up a storm on English shores since their arrivals, and helped United to a 3-0 win over Brighton on their debuts last weekend. The former even bagged herself an assist, as her pinpoint cross found the head of Jane Ross who duly scored the third.

Speaking about signing for United, Heath told ESPN: "I think a lot of people were kind of surprised [about the move to England]. I was itching to play football, to play in an environment where you're trying to go for titles. For me it was massive there was interest from Manchester United. To sign for such a club was important to me in my football career.”

Press, meanwhile, reaffirmed the ambition to claim silverware this season, stating: "I think here it's just going to all be about winning titles. That's the cups, it's qualifying for the Champions League, I feel like that's a title in itself, especially for a young club like Manchester United."

Time will tell if both stars’ trophy ambitions are to be realised, but with United now seemingly ready to challenge the likes of Chelsea, Manchester City and Arsenal for WSL glory, it promises to be a fascinating season ahead.