Nike shares have taken a hit after Duke freshman Zion Williamson’s sneaker ripped apart during last night’s game against North Carolina, leaving the basketball star with a knee injury that forced him out in the first half.

The incident, which happened just over 30 seconds into the game at Cameron Indoor Stadium in North Carolina, showed Williamson awkwardly crumpling to the floor after he attempted to plant his left foot, with the Nike PG 2.5 PE’s rubber sole dramatically splitting away from the rest of the shoe.

“His shoe broke,” former President Barack Obama pointed out from the front row.

In a statement obtained by ESPN, Nike wrote, “We are obviously concerned and want to wish Zion a speedy recovery. The quality and performance of our products are of utmost importance. While this is an isolated occurrence, we are working to identify the issue.”

It remains unclear whether Williamson’s shoes had been worn in the past.

Duke coach Mike Krzyzewski described the injury as “a mild knee sprain,” adding that “it’s stable.” However, investors’ reactions were less than stable — sending Nike shares into the red early Thursday morning. As of 10:30 a.m. ET, shares remained down 1 percent at $83.99.

The 18-year-old is undergoing further testing, with results expected today. Sportswear giant Puma took a shot at its rival immediately after the injury, tweeting: “Wouldn’t have happened in the pumas.” (The company soon deleted the post.) Puma ambassador and Boston Celtics point guard Terry Rozier also reacted. “Come on over to puma,” he wrote.

The No. 1 seeded Duke Blue Devils ended up falling to the No. 8 North Carolina Tar Heels, 88-72.

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