Sasuke UchihavsVegeta

Sasuke Uchiha at his peak wields the Rinnegan, the Eternal Mangekyo Sharingan, and a mastery of virtually every ninja technique. His Susanoo provides a building-sized chakra avatar, Amaterasu creates inextinguishable black flames, and his Rinnegan's space-time abilities let him teleport and swap places with objects. He fought Naruto — a character with planet-level feats — to a standstill. In the Naruto universe, Sasuke is an omega-level threat.

Vegeta, however, operates in Dragon Ball's absurd power tier. Even in his base form, Saiyan Saga Vegeta could destroy planets. By the time he achieves Ultra Ego, Vegeta is fighting at universal-to-multiversal levels, taking hits that would erase solar systems and getting stronger from the damage. His ki blasts dwarf anything in the Naruto universe by orders of magnitude.

Sasuke's genjutsu — his strongest hax ability — is the biggest wildcard. If Sharingan genjutsu works on Vegeta, Sasuke could theoretically trap him in an illusion and finish the fight. However, Dragon Ball characters have resisted mind control through sheer ki pressure, and Vegeta's pride and Saiyan willpower have broken him free from Babidi's mind control in the past.

The speed differential is also massive. Dragon Ball characters are explicitly faster-than-light by the Namek saga, and Vegeta in his current forms moves at speeds that make Naruto-verse combat look like slow motion. Sasuke's Rinnegan teleportation helps, but Vegeta's raw speed likely exceeds Sasuke's reaction time.