Tennis star Naomi Osaka surprised industry watchers by signing an endorsement deal with Nike, switching from the US sports brand’s biggest rival, Adidas AG.

The sports world had been anticipating that Adidas would pay a record sum to renew a clothing endorsement with No. 1-ranked Osaka, who seized global media attention by defeating Serena Williams at the US Open last year.

Nike didn’t disclose how much it paid or terms of the deal with Osaka in its statement on Thursday.