Federer thrashes Wawrinka 6-4 6-3 6-1 to reach Sunday's final
Djokovic beats Cilic 6-0 6-1 6-2 in first semi-final
Roberta Vinci stuns Serena Williams in women's semis
Unseeded Vinci ends Williams' hopes of calendar Grand Slam
Fellow Italian Flavia Pennetta beats Simona Halep 6-1 6-3
With neither woman blessed with a howitzer serve, we could see a few long rallies in this match. Halep is the slightly more mobile player and that serves her well in this game as she chases down a Pennetta smash and the Italian nets. Hold to love.
Image source, Getty Images* denotes next to serve
Halep begins the contest with a bludgeoning forehand winner into the corner. A couple of cagey rallies as both women feel their way into the contest, before Pennetta returns the favour with an emphatic forehand down the line. Another lengthy rally is ended cleverly by Pennetta when she reels Halep in with a drop shot and then sends a backhand into the open court, and that seals a nerve-steadying hold...
Image source, APHere we go...Pennetta to serve first...
The players are knocking up out there - Halep, who is carrying some rather heavy-duty strapping on her left thigh, has won the toss and elected to receive serve. Mind games...
Image source, BBC SportSimona Halep v Flavia Pennetta
Standing in her way is Italy's 26th seed Flavia Pennetta, who loves New York more than Frank Sinatra - she's made the last eight in Flushing Meadows in six of her last seven appearances.
If she can make it here, she'll make it anywhere, right? Well, not exactly - she's only ever made one quarter-final at the other Slams.
Anyway, she starts today's match as a definite underdog, but if you think a Halep victory is assured, consider this - Pennetta leads their head-to-head 3-1. And then consider this...
Image source, Getty ImagesSimona Halep v Flavia Pennetta
Simona Halep is bidding to reach her second Grand Slam final - you may remember her taking Maria Sharapova to three sets in last year's French Open.
The diminutive Romanian may stand only 5' 6", but she packs a mighty punch, as Victoria Azarenka found out in their pulsating quarter-final.
If she can make it through today, the Serena Slam might not be such a foregone conclusion as it seems...
Image source, ReutersWelcome to live coverage of semi-finals day at the US Open. Over the next few hours, we've got Serena Williams v Roberta Vinci, Novak Djokovic v Marin Cilic, and Roger Federer v Stan Wawrinka.
But first up, it's women's second seed Simona Halep of Romania against Italy's Flavia Pennetta.
America. The land where everything is bigger, and better.
The cars. The hot-dogs. The skyscrapers. The ridiculously protracted presidential contests.
And now, you can add to that list the tennis. Because this is a special king-size, jumbo, footlong semi-finals day.
Not only have we got Novak Djokovic and Roger Federer in action in the men's semis, we've also got the women's semis held over from yesterday - and that means a side order of Serena, and an extra helping of Halep.
Still hungry? Then let's get started...
Image source, Getty Images