Nike still reigns supreme in North America but Adidas is steadily gaining on the sportswear giant. According to reports, Adidas' sales in North America grew by 16% in the quarter through June, whereas Nike was up just 3%, ending a three-quarter stretch of negative sales.

The iconic Adidas Superstar and Stan Smith silhouettes were largely responsible for the brand's growth in the United States over the last two years, but now it's the beloved Ultra Boost that is creating a frenzy. Adidas execs credited its Ultra Boost sneakers, which grew by nearly 50%, for having a “significant impact” on its strong quarter.

“We’ve built one of the most converted franchises in our industry in the Ultra Boost. This continues with this franchise growing close to 50 percent in the past quarter. So we are a long way from being saturated," Chief Executive Kasper Rorsted said on an earnings call, according to the Footwear News.

“The gap between Nike and Adidas is not as large as it used to be,” said NPD sports industry analyst Matt Powell.

According to the Wall Street Journal,"Investors were worried that Adidas needed a breather after constant-currency growth of 18% in 2016 and 17% in 2017, which was partly driven by a craze for its Stan Smith sneakers. But the slowdown hasn’t been as dramatic as some feared. The stock leapt almost 9% in morning trading."

Footwear News reports that Rorsted predicts the early 2019 launch of the next generation of the Ultra Boost will mark the next leg of growth and propel it to the 1-billion-euro mark.