Not everyone was enthralled with the U.S. Open quarterfinals match between Serena and Venus Williams.

Forbes magazine was worried about Maria Sharapova.

Stephen A. Smith Cites Sexism As Reason Maria Sharapova Earns More Than Serena Williams In Endorsements

Serena is trying to become the first person in 27 years to win the calendar Grand Slam as well as her 22nd career Grand Slam title, and her older sister, a seven-time Grand Slam champion stood in her way.

Forbes posted an article before the match saying that the Serena-Venus matchup should've been tennis' answer to a Super Bowl featuring Peyton and Eli Manning playing against each other, but for some reason lacked the marketing cache.

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The media entity, however, posted a more-than-curious tweet about the Russian tennis player, linking a two-weeks-old article, during the middle of the match between the sisters.

That drew the ire of Serena and Venus fans.

"Given the suspicious timing of the tweet, the debatable nod to Maria Sharapova (who Serena has beaten 17 times in a row), and the fact that the article was old -- Williams supporters immediately called a foul and blew up Forbes' mentions for the rest of the evening," thegrio.com reported.

The issue of endorsement money among Serena Williams and Sharapova has been a recent topic of discussion.

The topic was heightened earlier this week when ESPN's Stephen A. Smith said he believed sexism is a factor in Sharapova's nearly double endorsement earnings than Williams, who has won more than four times as many Grand Slam titles (21-5) and has won 17 straight matches in their "rivalry."

"In any category, when it comes to women's tennis, whether it be on the marketing side or beyond, and the fact that she is second to Maria Sharapova, the fact that people say the things that they have said about her, that they seem to go out of their way to bring attention to things other than the performance, it ain't just about race," Smith said on ESPN's "First Take. "It's about sex as well, meaning gender, OK? There's more sexism than it is anything else."

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