Gaël Monfils says farewell to Grand Slam tennis after US Open defeat

The 40-year-old Frenchman, who is planning to retire at the end of the year, was knocked out 6-3, 6-4, 6-3 by Learner Tien, who at 20 is half Monfils' age. Monfils received a standing ovation after his final shot went into the net.