Mario Tennis Aces

Mario Tennis Aces puts players in the shoes of Mario as he journeys around an island on a role-playing game-like tennis adventure to find a quintet of "power stones" connected to the world's most powerful tennis racket.
It begins with basic tutorials that teach players how to hit a variety of shots, including trick shots and special time-pausing power shots.
As players move from location to location, they unlock challenges that force them to practice and exploit specific techniques and shot types. They'll also tackle puzzle-like challenges -- such as hitting a ball against a magic mirror in a haunted house -- and go up against boss-style enemies with special abilities that they must defeat in order to keep progressing. Mario's level and tennis stats improve with each event.
Outside the adventure mode, players can take part in short tournaments against computer-controlled opponents, set up matches against other players both in the same room and online, and try "swing" mode, which allows kids to wield their Joy-Con controllers like real rackets to hit the on-screen ball.