Kouritsuchuu Madoushi, Daini no Jinsei de Madou wo Kiwameru

After devoting his entire life to perfecting his skills, Zeph Einstein receives the highest accolade of the Crimson magicians. However, the following year, he uses a newly developed magic that can assess the true talents of a sorcerer and he finds that his Crimson magic is actually inferior to all his other skills... He realizes he has wasted all his years pursuing the magic he is most incompetent at, and the anguish propels him to create a magic that can take him back into time. He wakes up finding himself back in the body of his younger self. Together with the prodigy magician Milly and the handsome female swordsman Claude, Zeph goes on an adventure, and perhaps this time he'll be able to effectively and efficiently master his magic!

(Source: Alpha Manga)