There was already enough tension at the Rogers Cup in Montreal on Saturday night as Rafael Nadal took on his old rival Novak Djokovic in the semi-finals.
However, the intensity was cranked up a notch during the deciding set when Nadal struck his opponent in the face with a backhand at the net.
Djokovic was far from impressed, and it got worse for the world number one as he went on to lose the match 4-6 6-3 6-7(2) against the Spaniard.
Watch the video below to see the Serbian take one in the chops from close range: