Stan Wawrinka was struggling against Roger Federer at the Australian Open
Roger Federer had edged a tight first set 7-5 with Wawrinka chasing a second Australian Open final.
But the former world No 1 stepped it up a gear in the second set and his fellow countryman grew more and more frustrated.
Stan Wawrinka smashed a racket in frustration at his inability to break Roger Federer down
Stan Wawrinka appeared to be struggling with injury and left the court for treatment
And when Federer took the second set 6-3, Wawrinka left the court with tears in his eyes and a towel over his head.
The umpire confirmed that he was receiving an off-court medical timeout.
Wawrinka returned for the beginning of the third set with some minor strapping on his right knee and he seemed to be struggling pushing off.
Federer hit two crushing returns of serve in the first game but Wawrinka was able to hold before the Swiss cruised through a service game to put the pressure back on his opponent.