Speed equalization is not enough to save Dante here.
With their stats so close to one-another, the match can easily be decided by Spawn's A) far higher stamina and B) regen that doesn't deteriorate with loss of said stamina. (Unlike Dante's) In that particular case, the fight will only last as long as it takes for Spawn to wear him down to nothing.
However, if that isn't enough for you, Spawn has intangibility, telepathic teleportation of outside objects, pain manipulation (read: his ability to transfer the pain and suffering of the entire world to someone with a single touch), time-stopping, reality-warping and power nullification, none of which Dante has an answer for. Once Spawn starts up using those powers, this fight is going to turn brutal. Fast.
To recap, prettiest scenario? Dante gets outlasted. Ugliest scenario? Dante gets destroyed.