Pantheon IS SOOOOO GOOD. He counters many other top laners and has great mobility and roam potential. He is my Favorite champ just because he is the first one I bought and spent the most time on but it took me awhile to fully devise a plan to play him in the top lane competitively. The only real tip is focus super hard on rushing your first core item so CS well and make gold a priority. You want to take advantage of his early/mid game scaling as fast as possible as you should find getting kills in late game is a little harder.

PROS

Great Duel Potential
Doesn't have many true counters
Can dish out tons of Damage very fast
Best Champ

Cons

Not much escape utility
Late game Struggle if not tanky
W can be cancelled mid air by enemy cc ability which will reset its cool down timer.

Pantheon needs his team. I've carried games with him but teamwork makes dream work. Looking to do a level 6 roam is awesome possum because I use tp to get back to lane after I roam for mid or bot. Late game if you aren't the badass you were early just note you have 2 jobs, kill their carry's at all costs and defend yours. So sometimes dying isn't a bad thing as long as your side wins the fight.

OHHHH you better farm. YOU BETTER GET GOOD AT CREEPING THE SCORE. Rushing the B.F. is essential. Mid game you can use your E to clear a wave like a snake on buttered rice treats.