not through combat, by strategy. How will one defeat him?

Unpopular opinion, it’d be either cyborg (Viktor) because of integration of human intelligence ( and since he was a sportsperson so strategy making skill will be there) with artificial intelligence or else Green lantern (H.Jordan) because he was a aircraft pilot (US Air force) which requires certain strategic thinking and obviously he had THE RING.

I think cyborg, green lantern,green arrow, black Canary, flash.

Being a sportsperson would actually be someone that incorporates great athleticism and strength instead of smarts (a stereotype). But I like your take on it and I think Hal would be able to take Batman on. Maybe with help from other lanterns.

Flash, yes, he is very smart and has used his speed with his smarts to defeat many.

I think its green arrow or flash