This is a difficult skill-check for Briar. Jayce is a lane bully who wants to poke you from range and use his hammer knockback to cancel your engage. You win by baiting his cooldowns and forcing an all-in when he's stuck in his ranged form.
This is a volatile jungle duel where whoever uses their defensive tool better wins. Pantheon wants to burst you early with a point-and-click combo, while Briar wants to out-sustain him in long skirmishes. You must avoid engaging when his is at 5 stacks unless you have ready to soak the burst.
This is a hunter-prey dynamic where you are the hunter. Jayce is a squishy poke champion who relies on spacing, while and allow you to close the gap and force extended fights where he cannot compete.