Gragas should leverage his medium early pressure and strong objective control to contest river and dragon before Lillia can use her fast clear to out-tempo him.
Prioritize disrupting Lillia's tempo farming by invading or counter-jungling when lanes have priority and (E) is available for engage or escape.
Jungle Plan
Use flexible pathing to pressure lanes where (E) can force flashes or set up kills before Lillia completes her full clear.
Contest river vision and objectives aggressively when (R) is available to displace Lillia or her team from dragon or Herald.
Track Lillia's pathing to counter-gank her early ganks and deny her tempo advantage through selective invades and objective setups.
Danger windows
Avoid fighting when (E) is on cooldown, as you lose both engage and escape tools against Lillia's high mobility and sleep CC.
Beware isolated river fights where Lillia's movement speed and sleep setup can catch you off-guard.
Respect Lillia's power to contest objectives with high DPS and sleep CC, especially when your smite or (R) is down.
Early game
Start with a three-camp clear to maintain health and hold (E) for counter-ganks or early skirmishes near Scuttle.
Fight for first Scuttle only if nearby lanes have priority to back up your contest.
Avoid extended fights early if (E) or passive sustain is down to prevent being outpaced by Lillia's faster clears.
Power spikes
Level 6: Use (R) displacement to isolate Lillia or peel for your team, forcing her to respect your engage or disengage threat.
First AP or tank item: Trade aggressively around your burst or durability spike to win short trades and punish Lillia's lower sustained damage.
Level 3: Use full kit with (E) stun and (W) damage reduction to execute complete short trades and punish Lillia's early skirmishes.
Win conditions
Convert early river control and Scuttle vision into securing dragon and Rift Herald before Lillia can contest.
Use (E) and (R) to create pick opportunities or disengage enemy engages, enabling your team to capitalize on fights.
Deny Lillia free farm by invading or counter-jungling when lanes have priority, slowing her AP scaling and teamfight impact.
Tip: For Gragas vs Lillia, read overview, trading pattern, and danger windows first for a fast Jungle lane check.