Osaka edged Coupe Rogers champion Simona Halep, US Open finalist Williams, and Western & Southern Open champion Kiki Bertens to top this month's ballot.
The real reasons, however, are many.
"Whether you agree with her or not, there were issues that Serena wants to deal with and those conversations will keep going because she took a stand".
She is not young any more, however, she has recently become a mother, and she has not been playing as much as she used to.
The Japanese star defeated her childhood hero 6-2 6-4 in a highly controversial match which stunned tennis fans around the world. She was later fined $17,000.
A Williams rose to stardom, so did the racist attacks against her. While men play best-of-five-set matches, women play best-of-three-set.
Women's singles Champion Naomi Osaka of Japan poses for a portrait inside the Rockefeller Center on day fourteen of the 2018 US Open at The Rockefeller Center on September 9, 2018 in New York City.
Serena, in fact, has been the target of racist messaging that she isn't welcome in the sport she dominates.More news: Eight Killed as Florence Dumps 'Epic' Rain on Carolinas
In addition to her extraordinary tennis skills as displayed in her dominant performance against Williams in her first Grand Slam win, the Japanese-born athlete with a Haitian father is now also being recognized for her broad global endorsement appeal.
Murray, however, told BBC Sport that Williams' accusations of sexism are "a bit far-fetched", adding: "I've seen a lot of people get called for coaching before, and you might have a grumble and stuff, but you get on with it".
"But to focus on that, I think, is missing the point".
Apart from the possibility that the match may not have been over at the time, her behaviour can not be condoned.
Fearless, determined, fierce and aggressive, she matched Serena serve for serve, return for return, aggressively going for the shots that left the audience in disbelief. The biggest complaint in the Williams controversy was that Ramos called the third penalty - which cost Williams a game - for being called a "thief".
"It isn't the first time you have had to deal with unfair judgment against you, and yet you have this wonderful ability to come back with such courage and grace", she said, before steering the conversation away from the US Open drama.
"Because she is Serena", she answered with a girlish giggle.
"I always knew this would come back to haunt me", she said on Twitter.
"But if you were talking about my tennis, I think my tennis is not very Japanese". The crowd was a typical ratty US Open one.