Aryna Sabalenka talks about what she thinks about during an intense tennis match and going up against Nick Kyrgios in a Battle of the Sexes match before signing Jimmy's forehead for good luck. The Tonight Show Starring Jimmy Fallon. Stream now on Peacock: https://bit.ly/3gZJaNy Subscribe NOW to The Tonight Show Starring Jimmy Fallon: http://bit.ly/1nwT1aN Watch The Tonight Show Starring Jimmy Fallon Weeknights 11:35ET/10:35c Get more The Tonight Show Starring Jimmy Fallon: https://www.nbc.com/