Roger Federer is through to the semi finals of the US Open.
He won his quarter-final tie against Frenchman Gael Monfils last night after a stunning comeback.
The second seed came back from 2 sets down to love down and also survived two match points late in the fourth set, before winning 4-6, 3-6, 6-4, 7-5, 6-2.
He will now face Marin Cilic in the last four.
Cilic beat Tomas Berdych in straight sets last night.
