Pantheon's q is longer than most toplaners and they are mostly meelee so it is easy to proc first strike for the ones that are harder to proc go hexflash instead of magical footwear to cheese in bush. His high damage enables him to steal immense amount of gold and can accelerate him into mid game so that he doesnt fall off.

Eclipse unlike the other lethality item provides shield and ms which is sometimes crucial in trading and also in teamfight synergising with his e to run away. bork is THE perfect item for panth because of his empowered w attacks that means he can take out 40 percent of the enemies max health in one click. THis also synergies with his q's execute thats under 20% max health. Depends on the comp you can choose between black cleaver and LDR for either functionality or super high damage both synergies with his R passive of the penetration. essense reaver enables pantheon almost to never back because the mana sustain and the super high damage. Collector provides ilethality and crit and the execution gold is a small but gradual step towards our capital economy.

Pantheon's Laning Phase is not hard, remember to always poke with q and try to cooporate with the jg. Basic combo is empowered w q a e or 4 stacks passive w q a e
If the opponent has no mobility it is better to use empowered w then a e or e a then q for the most damage.