Roger Federer against Rafael Nadal - The pair have never met at Flushing Meadows in the seven years that they have both been playing here.
In fact, they have not played on US soil since Miami in early 2005 when Federer hit back from two sets to love down to win in five sets, the first and only time that has happened to Nadal in his career.
First, though, they must win their semi-finals, top seed Nadal against Russian 12th seed Mikhail Youzhny and five-time former winner Federer against third seed Novak Djokovic.
In fact, they have not played on US soil since Miami in early 2005 when Federer hit back from two sets to love down to win in five sets, the first and only time that has happened to Nadal in his career.
First, though, they must win their semi-finals, top seed Nadal against Russian 12th seed Mikhail Youzhny and five-time former winner Federer against third seed Novak Djokovic.
On the face of it, Federer has the toughest task ahead.
Djokovic has gone from strength to strength over the last 10 days, scraping through his opener in five sets before impressing in his quarter-final thrashing of dangerous Frenchman Gael Monfils.
But he has lost in the last three years here to Federer, dropping a final in 2007 and semi-finals in 2008 and 2009 and has won just one set in the process.
It will, he agrees, be a monumental task he faces on Saturday.
