Naomi Osaka has added Mastercard Inc. to her endorsement contracts, as the No. 1 ranked tennis player continues to attract sponsors following her wins at the U.S. Open and Australian Open.

Osaka, who wore the Mastercard logo on her visor during her first match at the Madrid Open this week, tweeted about the deal, which was confirmed by her talent agency IMG in an emailed statement. It was the tennis star's seventh corporate endorsement since she won the U.S. Open in September.

The Mastercard deal comes a month after Osaka surprised industry watchers by signing up with Nike Inc., switching from the U.S. sports brand's biggest rival, Adidas AG. Nike has traditionally prohibited tennis stars it sponsors from displaying other brands or logos on its clothing, a barrier IMG broke through with a deal to allow shoulder patches for Chinese tennis star Li Na in 2009.

Mastercard will gain valuable real estate on Osaka's outfit, joining patches on her shirt from instant noodle maker Nissin Foods Holdings Co. and airline ANA Holdings Inc.

International brands from Nissan Motor Co. to Shiseido Co. have signed Osaka with an eye toward building their brand globally. Osaka's mother is Japanese and her father is Haitian American.

IMG declined to disclose the terms of Osaka's Mastercard agreement. Mastercard didn't immediately respond to an emailed request for comment.

Osaka has won the last two Grand Slams. She became the first Japanese singles player to win one of the four majors when she overcame Serena Williams at the U.S. Open.

Her ascent to the top of the women's game has made her a hot commodity for the world's top brands. She also has deals with watch company Citizen.