It's only the first day of the 2017 Australian Open and we may already have our highlight of the tournament.

Well, it probably wasn't a highlight for poor Martin Klizan, who opened play against world No. 4 Stan Wawrinka on Monday.

Klizan, No. 34 in the world, was on the verge of an upset when something ... unexpected ... happened. Tied at two sets apiece and 4-4 in the fifth set, Klizan approached the net and lofted a short volley in Wawrinka's direction. Disgusted with himself, Klizan stood still and waited for Wawrinka to smash home the winner.

Unfortunately for Klizan, Wawrinka's aim was just a little bit off.

OUCH, indeed. Here's the full video so you can relive that magical moment in its entirety.

At least Wawrinka, clearly sorry for unintentionally nailing Klizan where the sun don't shine, hopped over the net to apologize and offer his condolences.

To add insult to injury (literally), Klizan lost the next two games and fell to Wawrinka, 4-6, 6-4, 7-5, 4-6, 6-4.