this a game. Primarily for everyone to have fun in.
Hells Yeah! It's only comic book characters after all. We could always argue about less controversial things like politics, religion, capital punishment, abortion, foreign policy, etc.!
But seriously though, at first I thought it was an easy GL victory. I love Captain America but he just seems to be completely out of his power class. Green Lanterns (Hal in particular) have unimaginable power literally at their fingertips and are only hampered by their own limitations.
Cap has certainly held his own against, if not defeated, numerous adversaries that were way more powerful then he.
Michael Korvac was a being with god-like abilities who had basically just wiped out both the Avengers and the Guardians of the Galaxy, including Thor, Iron Man, Star-Lord, Vision - single handedly, no less. And then Cap did this:
Granted, he did lose in the last panel but what if Korvac had been wearing a removable ring that gave him his powers?
Not to take anything away from Hal Jordan but Steve Rogers indomitable will has helped him go toe-to-toe with many opponents who were more powerful including Cosmic level foes like Thanos, Ultron, Thor, Hulk, Iron Man and a certain Dr. Victor von Doom who had usurped the power of the Beyonder in Secret Wars.
I think the Wild Card here was the choice of location. (Very clever, Clint!) It is my belief that Cap will definitely use this to his advantage. Sure, Hal can scan it with his ring but for Cap it is his home field. My guess is that he would be able to lure Hal to a spot where he has access to more sophisticated means to incapacitate a Green Lantern. I'm sure S.H.I.E.L.D. has a few thingies lying around that Steve could pick up and utilize. Anyone remember the Zodiac Key?
There's probably at least a dozen such objects at hand.
After mulling it over, I think that I am going with Captain America. If it was in a different environment then I would probably feel differently.