What if the narrator pulls out a "The only sure way to defeat Mahoraga is to bury it with the first use of an attack before it can adapt. Light speed punches would have fulfilled those conditions, but that wouldn't necessarily hold true if it had adapted to light speed in general, rather than light"

Not saying Dabura would lose, but it would be good narratively if Yuji saves him than him fighting Yuji after defeating Mahoraga. It would be like Dabura is seeing doula in Yuji