Sinestro is one of the most powerful lanterns of alltime, but loki is the "God of Mischief" and is very smart combatant, and has many tricks up his sleeve to trick Sinestro with. To start of with, Loki has the power to summon at will, a magical blade that is strong enough to shatter Asgardian swords and is hot enough to scorch Thors skin without even touching him. This is pretty standard for Regular Loki. Magical stones given to Loki by Karnilla called "Norn Stones" that he can use for a multitude of different uses, like rearranging his molecules, amping the Avengers and changing the terrain around him. Loki has an entire arsenal, and he also has the brains to use them well in fight.
Let me guess, Batman needed "prep time" to make those bombs or to even figure out his weaknesses. Now you tell me (in a completely random incoubter) who wins now that Batman doesn't already know Magneto's weakness. It doesn't take a genius to figure this one out!🤣
