Tennis players are notorious for being superstitious with everything from their pre-match meals to the ball they serve with. In Houston, the players were asked for their biggest superstitions in honor of Friday the 13th. 

Nick Kyrgios revealed he used to watch horror movies on Friday the 13th and would get scared, but no longer—he's almost 23 after all. Tennys Sandgren admitted he reuses his underwear when he's winning, but that was a joke, obviously. Next time you see Miami Open champion John Isner play, watch out for his habit of bouncing the ball between his legs before serving.