Only StarCraft and Dots can defeat him. Other than that, he's unstoppable, in fact he can actually beat Starcraft and Dots in his Mega Evolution form.
Starban is even more broken in Brawl 1 than he is in Brawl 2 and Brawl 4. He does not appear in Brawl 3 due to the techlessness of said game. He is the only character who can hit through Connery's invincibility. Giant Link is known as one of the few characters to not have a -4 matchup against Starban, as his grab potentially outranges Starban's OHKO attacks, and he has zero-to-death chaingrabs. However, Starban can still combo him into oblivion.
He's also says this wiki is fucking bad. WHICH IS CORRECT. ALL YOU TECHLESS NINTENDOS BOW DOWN. STARBAN. OUR LORD AND SAVIOR. he is here