This is a pretty bad matchup for Dabi. His fire abilities are strong but Deku can blow them away with pure power. At that point Dabi has no other defenses which can get pretty tricky for him. Deku also has enough power to end this in one punch since Dabi doesn’t exactly have any more durability than an average person. So while Dabi is a pretty important villain, he wouldn’t last more than a few seconds against Deku. Deku wins.