Adidas' rise has come at the expense of Nike. Picture / Wikimedia Commons.
For the first time in their modern rivalry, Nike has reason to fear adidas.
When it comes to footwear, the swooping tick has always been untouchable, but dramatic sales figures released by a market research company in the United States means Nike is looking over its shoulder.
The NPD Group's August athletic footwear data report released on Tuesday (AEST) shows adidas has jumped Nike's Jordan "Jumpman" brand to be the No. 2 brand in athletic shoe sales in the United States.
The resurgence of adidas is nothing surprising for footwear market experts, but the speed at which adidas has rolled over the Jordan brand has shocked them.
NPD sports industry guru Matt Powell says the shake-up of the industry is both the result of adidas nailing its recent releases to give customers exactly what they want while the Jordan brand took a major hit as demand for basketball retro continues to decline.
"It came faster than I expected. I thought it wouldn't happen until next year," Powell told Benzinga.
"They (adidas) are really customer centric. They are making products that the kids want to buy.
"Nike let the Jordan business get overheated, which slowed down the liquidations. The sentiment on Twitter is that Jordan is not cool anymore, which is overblown. But there is no question that retro Jordans (are) not selling out immediately like they used to."
Jordan sneakers, styled and made famous by NBA legend Michael Jordan, make up half of Nike's total sales of basketball shoes in America, making it a giant player in Nike's fleet of high-profile shoe brands.
However, in the space of 18 months, Jordan's retro kicks have gone from being the second biggest player - on their own - in the US footwear market to playing second fiddle to a brand it was doubling in sales just 24 months ago.
It is a huge hit to Nike's reputation and bank balance.
In 18 months, adidas has almost doubled its share of the $US1.86 billion ($2.56b) athletic footwear market in the United States.
The company's rise has come at Nike's expense.
In May 2016, a NPD market analysis showed adidas' total sales for athletic shoes made up just 6.7 per cent of the total market.
At the same time Nike's Jordan brand alone accounted for 11.8 per cent of the total market.
The NPD report shows that in the past 12 months the German apparel giant has exploded to now make up 13 per cent of the athletic footwear market on the back of an increase in total sales of almost 50 per cent from the previous 12 months.
At the same time the Jordan brand lost almost one third of its annual sales as the American basketball sneaker industry also took a hit of more than 20 per cent of annual sales from the previous financial year.
As the basketball shoe market dropped 20 per cent, adidas' basketball production achieved an increase in total sales of more than 40 per cent.
It's the first time in more than 30 years Nike has not owned the top two shoe brands in the United States and a situation many experts didn't think Nike would ever have to confront.
The crashing sales of Jordan brand shoes is a big concern for Nike, but the bigger picture is even scarier.
The same reports show Nike's fleet of shoe brands has been slashed from a 60 per cent share of the market in 2014 to just 44 per cent of the total sneaker market, according to the report released by NPD.
While Nike's total market hold remains imposing, the storm clouds are gathering.
Quartz fashion industry expert Marc Bain has reported Nike has every reason to be worried about the momentum adidas is gaining.
He says adidas deserves plenty of credit for leading the industry in the past 18 months in both design and technological advancement.
For the first time in more than a decade, Nike did not have the top-selling sneaker in America last year - adidas stole top spot with it's re-fashioned "originals" retro superstar.
The new line of NMD adidas sneakers released this year has also surged in popularity.
Bain reports adidas has been setting the agenda in sneaker technology, with its new Boost soles and exclusive springy technology meeting market demands.
This is widely reported to be the area where Nike has dropped the ball.
As adidas has driven technological advancement, Nike has been accused of trotting out the same sneakers year-on-year, especially in its Jordan brand division where its retro Jordans are losing their edge and the interest of a market which has been moving away from basketball shoes towards other forms of streetwear.
Market analysts predict Nike's title as the top dog in sneakers is safe at least for now, but the threat to their throne is real if the company doesn't get its house in order.
"Nike has dominated the sneaker world for so many years that it has come to seem invincible, particularly in the US, its home turf and the world's biggest sneaker market," Bain wrote recently.
"Lately, though, some holes have started to open up in Nike's armour. For the first time in ages, Nike's iron grip on the sneaker world is visibly slipping."