Sasuke was in control of curse seal. The only thing thst would mind happened is to kill Yoroi. If he would have used curse seal he would have be disqulified,while Naruto was using kyuubi chakra similar to curse seal and still wasnt disqulified.
Sasuke vs Yoroi
So if Sasuke used cursed seal he would have been disqualified
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Naruto vs Neji
- Naruto was using Kyuubi chakra to win the battle and still wasnt disqualified