What build do you even go on Pantheon
From my experiments the recommended build seems to be complete dogshit, going cleaver gives you nothing and leaves you with 0 mana, Ghostblade rush is fine but leaves you too squishy to actually duel and with no sustain (same for cleaver).
Deaths Dance / Trinity rush has proven to be the best for me tbh, going DD with ravenous hunter and conq gives you good sustain in fights and makes you more tanky as a result of DD passive and trinity gives you both mana to keep you on the field for longer, attack speed to help stack passive and Sheen proc helps you burst (move speed is also nice for chasing targets)