Accelerator is the strongest Level 5 Esper that there is and his convincing victory over Misaka definitely proves this. Mugino was also able to give Misaka a good run for her money, but her abilities are not well suited to fight Accelerator. Bending vectors and shifting energy blasts is what Accelerator does best so this should be a quick win for him. None can stand up to his power! Accelerator wins.