Suggested by Destroyer Megaman SF is one of the strongest Megamen in the franchise. He has a ton of forms and techniques and is one of the strongest in the verse. Of course Protoman is one of the strongest in the most powerful timeline which is Exe. He’s held his own with Megaman on numerous occasions and is good at fighting this kind of opponent. I think ultimately SF will be outmatched here. He just won’t be able to keep up with Protoman in the long haul and would lose after a hard fought battle. Protoman wins.