Tennis icon Serena Williams stunned as Will Smith and Chris Rock clash at Oscars

Tennis superstar Serena Williams seemed lost for words on Instagram as the 23-time Grand Slam title winner broadcast live from the Academy Awards ceremony where Will Smith, who won an Oscar for his portrayal of her father in biopic 'King Richard', slapped Chris Rock and shouted obscenities at the host over a joke he made about the actor's wife, Jada Pinkett Smith.

In an incident which drew headlines around the world, furious Hollywood icon Smith assaulted comedian Rock over a joke he made about Pinkett Smith's alopecia.

Smith then swore at Rock before tearfully apologizing on stage while accepting an award for his role as Richard Williams, Serena and her fellow tennis champion sister Venus's father.

In footage that many fans have interpreted as a reaction to the controversy, Williams appearing open-mouthed for several seconds on her social media video and  said: "I just sat down because I was like, 'I've got to put that drink down.'"

Williams, who wore a glamorous Gucci dress for the occasion and attended with husband Alexis Ohanian, called the event "surreal".

"I am so grateful to the Academy Awards for making this an unforgettable night, and to Will Smith for bringing this story to the big screen and honoring my family," added the all-time great. "This will always be a night to remember."

Tech chief Ohanian shared news of the altercation and a video of Smith collecting his Best Actor Award.

The clip showed Smith revealing that actor Denzel Washington had told him after the confrontation: “At your highest moment, be careful. That’s when the devil comes for you.”

"Art imitates life," added Smith. "I look like the crazy father, just like they said about Richard Williams. But love will make you do crazy things."

Elder sibling Venus Wiliams also kept her millions of online fans informed as she enjoyed the most high-profile awards event in the film industry.

The seven-time Grand Slam title winner admitted she did not "know how to act" around former award-winner Al Pacino and spoke to legendary actor Anthony Hopkins.

"I've tried my best to prepare for every moment in life," she said. "I’ve trained my mind, body soul and spirit to be prepared and ready for anything that comes my way – until now.

"I could have never dreamed or prepared to be at the awards for a film that tells my family's story.

"This is beyond my dream. What can I tell you? Keep dreaming. Keep working. Keep fighting.

"You don’t know where life might take you. I’m from Compton, California. And now I’m allowed [all] the way here. Its so good to be alive."

Neither sister has played a competitive match this year. Serena is currently ranked 240th in the world, with Venus 466th.