I Played Tennis in My Past Life, and Sukuna in This One

Lugong Xiang is a tennis player. After barely defeating a group of monstrous high schoolers who could unleash otherworldly powers and winning the world championship, he accidentally transmigrates to another world. His parents are alive, his family is happy, and he has plenty to eat and wear. Apart from a dormant System, it's a perfectly ordinary transmigration. Then, when he's five, he encounters a cursed spirit charging at him with a roar. At the moment of life and death, the System activates. [The Tennis God System has been unlocked. Host, complete your mission and defeat the King of Curses!] Lugong Xiang: ? You mean I have to use tennis to fight cursed spirits? Remembering the monstrous tennis skills of the junior and senior high schoolers from his previous life, Lugong Xiang realizes a little late: Wait, maybe that's not impossible? Ten years later, Lugong Xiang enrolls at the technical college. On his first day, he teams up with a classmate for a mission. He uses Atobe Kingdom, seeing through his opponent's weaknesses, and easily defeats the cursed spirit. Gojo Satoru: Wow, you have special eyes too! Lugong Xiang: No, this is tennis. Gojo Satoru: ? When they encounter a special-grade cursed spirit, Lugong Xiang uses his ultimate defense, the Black Hole, and easily defeats it. Gojo Satoru: Wow, your technique is a bit like Limitless! Lugong Xiang: No, this is tennis. Gojo Satoru: ?? In their second year of high school, they encounter the Heavenly Restriction. Lugong Xiang uses Five Senses Deprivation, Light-Speed Ball, and Giant Form, and successfully defeats his opponent! Fushiguro Toji: Seriously, how many different techniques do you have? Lugong Xiang: No, this is tennis. Fushiguro Toji: ??? When they encounter the special cursed spirit Mahito, Lugong Xiang uses Demonization and Crucifixion, successfully defeating the cursed spirit. Mahito: Which one of us is the cursed spirit here? That was downright underhanded. Lugong Xiang: No, this is tennis. Mahito: ???? Years later, during the final battle, the King of Curses kills all the strongest fighters in the jujutsu world. Just then, Lugong Xiang makes a dramatic entrance! He uses Phoenix Rebirth. Everyone comes back to life! Sukuna: You know Reverse Cursed Technique? Lugong Xiang: No, this is tennis. Sukuna doesn't understand, but is deeply shocked. So tennis becomes this dangerous a thousand years from now?! Lugong Xiang expands his domain. Tokyo turns into a tennis court, flying saucers appear, and aliens descend. Lugong Xiang: Let's play a thrilling game of tennis for the sake of our lives! Theme: Do we really have to play tennis?