Defiant is a "tough little ship" from what we saw throughout the Dominion War.
Voyager slaughtered Borg cubes due to they're transphasic torpedoes or whatever Adm Janeway brought from the future. I can't imagine they would work on a ship that doesn't analyze and adapt to everything like the Borg do.
The Enterprise-E is a "tough big ship" as we saw from First Contact and Nemesis. Big E takes this battle.
Yeah... Fighters have know future against big starships.