Serena Williams has the support of sports royalty: King James.

LeBron James said he backs Serena following her controversial US Open final loss to Naomi Osaka earlier this month.

Watch: Osaka's Rewards, Serena's Secret

The 23-time Grand Slam champion charged chair umpire Carlos Ramos with a sexist ruling after Williams was docked a game for a verbal abuse violation in the second set of her 6-2, 6-4, loss to Osaka.

The former world No. 1 berated Ramos as "a thief" and repeatedly demanded an apology after the veteran chair umpire hit her coach, Patrick Mouratoglou, with a coaching violation warning.

The NBA superstar told The Hollywood Reporter Williams' battle is for more than just the Flushing Meadows final, he says it's a fight for equality.

"What we all have to understand is what she is fighting for is bigger than just that match," James said. "She is fighting for equality—always having to win more, more, more, just to feel equal. Being an African-American woman playing in a predominantly white sport, she's dealing with so much more. I have no idea what was going on in her head, but I feel that struggle."

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