(CNN) One of Naomi Osaka's Japanese sponsors has apologized after releasing an advertisement which has been widely accused of "whitewashing" the tennis star's skin tone.

The 2018 US Open winner is featured in the ad as an anime character for instant noodle giant Nissin, alongside fellow Japanese tennis player Kei Nishikori.

Critics allege the cartoon depicts Osaka, who is half Japanese and half Haitian, as having pale skin, light brown hair and Caucasian features.

A screengrab from a commercial produced by Japanese noodle maker Nissin, featuring tennis stars Naomi Osaka and Kei Nishikori.

"I was truly disappointed to see that there was no woman of color to speak of in the commercial. Instead, I found a white-washed representation of Osaka," Baye McNeil, an African-American columnist who writes for the English-language Japan Times, said in his "Black Eye" column.

Noodle maker Nissin said that it did not intend to whitewash the 20-year-old tennis star, who holds dual Japanese and American citizenship.

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