Tati began playing for Nantes' Under-17s team when he was still 15, and was then promoted to the reserve team at the back end of the 2024-25 season. He helped Nantes reach the final of the U19 Championnat, where they were beaten 2-1 by PSG, though the disappointment of failing to win a youth title did not last long as Tati had still managed to impress the first-team coaches, who invited him to spend pre-season training with them.
Tati stood out in the pre-season campaign and was named in the starting XI for the first Ligue 1 game of the season, at home to PSG. The recently-crowned treble winners won 1-0, but Tati barely put a foot wrong, earning glowing reviews from the local and national press. L'Equipe said the teenager "was never in trouble" as he marked Goncalo Ramos out of the game ashe only time the Portugal forward got ahead of the debutant was when he caught offside.
"He played a very good match, he's calm, focused, and at 17, that's not bad," said coach Luis Castro, who has only not selected Tati this season when he was nursing a minor injury. Tati's 13 starts make him the most-used player under the age of 18 in Europe's top five leagues, while his rise has also led to an embarrassing situation for 31-year-old Serbian defender Uros Radakovic, who was signed in the summer but has played just four games, all as a substitute, due to the teenager's consistent displays.
In October Tati signed his first professional contract, tying him to Nantes until 2028 with the option to extend the agreement until 2030. But it is highly unlikely he will remain there that long. United, Arsenal, Bayern and Barcelona are just some of the clubs that have sent scouts to watch him in action, while PSG are tracking his progress too.