Shares in the sportswear giant Nike tumbled Thursday after a star college basketball player was injured when his sneaker malfunctioned during a high-profile rivalry game.

No. 1 Duke's Zion Williamson, who is expected to be the top pick in this year's NBA draft, sustained a knee injury after his shoe split open just 33 seconds into a game against No. 8 North Carolina.

The sportswear company was quick to point out that the problem was an "isolated occurrence," but its shares were still down 1.6% as of 10:40 a.m ET.

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Shares in the sportswear giant Nike were sliding Thursday after a star college basketball player was injured when his sneaker malfunctioned during a high-profile rivalry game.

No. 1 Duke's Zion Williamson, who is expected to be the top pick in this year's NBA draft, injured his right knee when his Nike 2.5 PE's exploded just 33 seconds into a game against No. 8 North Carolina. He missed the rest of the game, which North Carolina went on to win, 88-72.

Nike shares were down 1.6% as of 10:40 a.m ET on Thursday.

"We are obviously concerned and want to wish Zion a speedy recovery," Nike said in a statement, per Bleacher Report.

"The quality and performance of our products are of utmost importance. While this is an isolated occurrence, we are working to identify the issue."

Duke basketball players have been wearing Nike since 1993. Williamson's recovery timeline is unclear, as is the effect his injury will have on the top-ranked Blue Devils' chances this season.

The incident was viewed in person by former President Barack Obama, who could be seen in the crowd saying "His shoe broke."

—ment nelson (@mentnelson) 21 February 2019

Williamson, 18, was sent messages of condolences by well-wishers including Obama and LeBron James.