I can recommend the Doujinshi novel, Star of the Net King, Noyuko. The main character of the novel accidentally transmigrated to the world of the tennis prince and fought side by side with the players of the Qing School. His skills were revealed, and he fought with Ryuuma and the others at the peak of tennis. Although there was no explicit mention of transmigration in the text, the protagonist's superb tennis ability and the plot of fighting with Ryuuma and the others met the requirements described in the question. I hope you like this fairy's recommendation. Muah ~😗