2. Loki Vs Selena
There aren't many fellow magic users in live action comic book movies for Loki to go up against, but Selena is certainly one of them. Tom Hiddlestone's interpretation of the god of mischielf has shown some signs of good but more obvious signs of evil, being the antagonist that led an alien army (the Chitauri) to attack the Earth. He is cunning and manipulative, whilst also possessing the physical prowess to stand up to his brother Thor in combat, making him a threat on more than one level. Power wise, he is a highly adept combatant, very physically strong thanks to his Asgardian upbringing and Frost Giant heritage and can throw grown men across a room, he is durable to the extent that he can completely shrug off bullets and take a beating from Hulk and come away relatively unscathed, he is quick and astute enough to catch an arrow fired at him from behind, while his more esoteric powers allow him to cast illusions, telekinetically movie objects and generate extremely cold temperatures, such as when he froze the lightning in the Bifrost Bridge to jam its functions. His main weakness is his ego, which tends to get the better of him. Selena, on the other hand, was nothing more than a would-be witch until she discovered the Omegahedron - a powerful magical item which imbued its wielder with mystical abilities. As a result, she was able to cast spells and create potions. She used a love potion on a guy, she made a construction vehicle come to life and do her bidding for her, she was able to dump Supergirl in the eternal void known as the Phantom Zone, she made herself in to a "princess of Earth" and was able to summon a giant monster to do battle with Supergirl. Powerful? Yes. Enough to defeat Loki? Unlikely.
Winner: Selena's only human (and, as such, has human vulnerabilities), gained her powers artificially and didn't display close to as much prowess in battle as he did - Loki.