Sunny wins comfortably.
Make it Daredevil and Iron Fist and allow everyone all their gear/abilities, and it would be a more interesting fight IMO. Because then the Iron Fist or Sunny's swords have the potential to oneshot (as hard as Dark Ones hit, they don't hit as hard as Danny, and Sunny has been rocked by their strikes before), while Matt can help compensate for the stat edge Sunny has to make it more balanced.
The writers have current Sunny putting up a decent fight against a bloodlusted Dark One, while holding back himself. Yes, he did lose in the end, but I don't see Danny doing remotely as well, especially without the Fist.
And to give some context, a far less-skilled and experienced MK, who couldn't even control his gift back then, wrecked a Baron and entourage with zero effort, back in S1. From around 2:50:
On a random note, I miss Cyan. That guy was a beast.