And the mome rath
The Crystal outgrabe
What a stupid question.
Squall needed his friends to beat Summon(s). Seifer killed one in a single strike.
Squall needed the help of the party(again) to fight Seifer. But Seifer was alone(at least in the last battle at Lunatic Pandora).
Unless Squall got stronger after killing the monsters in Ultimecia's Castle, the answer to this question is obvious.
Not that simple. *hint* - Squall's limit breaks.