Fans at Flushing Meadow must have thought they'd turned up at the wrong event.
There they were expecting to watch a game of tennis, when out walks an extra from a Christina Aguilera video.
Oh no, hang on a sec, on closer inspection it's former world number one Serena Williams showing up for work in knee-high boots and a denim mini-skirt.
Easy mistake to make.
Question is, what look is the shock frock queen going to employ for her second round match?
Here's a few ideas, Serena...
Anyone for tennis?
The all-in-one suit was a popular accessory for swimmers and athletes alike in Athens, so why not take it that one step further?
She's already got the nails - and with all that slinky black leather on display, Serena is bound to leave her opponents feline inadequate.
Never mind Batman, she'd have Hen-man for breakfast.
Lieutenant Uhuru from Star Trek
A true legend of the small screen, Star Trek's Uhuru always looked debonair in her racy red tops, phaser gun at the ready.
And if Serena ever found herself getting embarrassed by a young upstart at a Grand Slam, there's only four words she'd need to save the day: "Beam me up, Scotty!"
Serena could floor her opponents
Some might (cruelly) suggest the younger Williams has already got the right physique to go a few rounds in the ring.
You can just imagine her squaring up to Laila Ali in, say, 'The Murmur in Burma'.
And maybe Serena would rediscover her famous killer punch by striding on to court with her gloves on.
Dr Who's arch-enemies are well and truly in at the moment after the BBC won permission to use them in the latest edition of the sci-fi series.
Unfortunately, Davros' creations are not renowned for their climbing abilities and Serena might have a bit of trouble leaping up for a forehand smash.
But if the American finds herself on the verge of defeat, she's always got the handy "exterminate" option to well and truly outwit her opponents. Forever.
It's two sets to one
Beach volleyball star
The skimpy, laid-back look was a familiar sight in the Oympics, as long-legged beauties jostled it out at the net.
And that was just the tennis.
Serena could walk straight into a beach volleyball game without changing her usual court attire.
Well, she might have to cover up a little bit.