Carlos Alcaraz says he has "enough battery to pull off some good things" after helping Team Europe race to a 3-1 lead over Team World on the first day of the Laver Cup.
Spanish world number one Alcaraz is competing in his first tournament since winning the US Open earlier in September.
He partnered Czech player Jakub Mensik to seal a 7-6 (9-7) 6-4 win over Team World's Taylor Fritz and Alex Michelsen on Friday.
Norway's Casper Ruud had put Team Europe's first point on the board in San Francisco with a 6-4 7-6 (7-4) victory over American Reilly Opelka.