Roger Federer and Stan Wawrinka will meet in an all-Swiss semi-final at the US Open after impressive wins over Richard Gasquet and Kevin Anderson.Seventeen-time Grand Slam champion Roger Federer did not face a single break point as he beat Frenchman Gasquet 6-3 6-3 6-1 in just 87 minutes.Wawrinka made almost as short work of Andy Murray`s conqueror Kevin Anderson, beating the South African 6-4 6-4 6-0.Top seed Novak Djokovic will face holder Marin Cilic in the other semi.