Meghan Markle cheers on Serena Williams at US Open final

The Duchess of Sussex flew to New York to support Serena Williams at the US Open final - but she also managed to sneak in a birthday surprise for another pal.

The Duchess of Sussex has been left disappointed after her friend Serena Williams lost the US Open final.

All eyes were on Meghan at Arthur Ashe stadium where she was seated in the tennis star’s box in front of Vogue editor-in-chief Anna Wintour.

Williams had been attempting to win her historic 24th Grand Slam in her clash with Canadian Bianca Andreescu.

The royal flew commercial to New York to support Williams, leaving Prince Harry and baby Archie behind in Windsor.

The Duchess of Sussex sits in front of Anna Wintour at the US Open final. Picture: Getty

Meghan, Duchess of Sussex, embraces Alexis Ohanian, entrepreneur and husband of Serena Williams, before the match. Picture: Getty

While back in the US, Meghan also managed to surprise her close friend, makeup artist Daniel Martin, for his birthday.

Martin - who did Meghan’s makeup for the Royal Wedding last May - shared an image of a plate of cupcakes on Instagram, along with the caption: “I am so overwhelmed by all of your well wishes! My sincerest gratitude! Thanks to everyone for reaching out to me today and Meg, love you friend for surprising me on my special day.”

It comes amid reports the Duchess of Sussex has set her new public relations team the target of “breaking the internet”.

Meghan rocks a denim dress as she watches her pal Serena Williams.

The lofty agenda has been revealed amid whispers among royal watchers that she prioritises her Hollywood image above her royal duties, according to the New York Post.

Meghan Duchess of Sussex. Picture: Doug Peters/EMPICS

“Meghan is creating a team that is not bogged down by the traditions and regul­ations of the Palace to work for her and Harry on passion projects,” a “senior royal source” told The Sun.

Meghan reportedly hired Madison Avenue PR firm Sunshine Sachs ahead of the launch of her Vogue UK guest editing gig in July.

“Even though it was the UK version of the mag, she wanted maximum coverage in America, which is the country she really cares about in terms of the media,” The Sun source reportedly said.

Meghan is in New York to watch the US Open. Picture: Getty

That’s when Markle announced her to goal to “break the internet” — a phrase popularised by Paper Mag’s provocative 2014 spread featuring a fully nude Kim Kardashian.

“It made her sound like a celebrity wanting to publicise a new album or movie,” the source scoffed.

Engaging the American press is Markle’s method of playing both sides of the pond, a second royal watcher speculated.

Meghan and Prince Harry. Picture: AFP

“This is Meghan’s way of being able to get a Hollywood answer to a question if she’s not hearing what she wants to from the Palace,” the second source said, adding it’s “a dangerous precedent to set.”

“There is a reason why courtiers and advisers treat members of the Royal Family differently — they are not celebrities, they are publicly funded official figures with a formal role.”

Meghan has faced a slew of criticism and rumours about allegedly diva-like behaviour.

A source told the New York Post she flew commercial to New York after media criticsm of her private-jet trips.

Sunshine Sachs reportedly joins former Hillary Clinton advisor Sara Latham and Hollywood talent agent, Nick Collins, on her PR team.