Use ranged spacing and (Q) repositioning to pressure Gragas and avoid his engage tools.
Prioritize denying Gragas short burst trades by controlling wave state and punishing missed (E).
This is a scale-oriented matchup where Vayne aims to outduel and kite Gragas through superior mobility and true damage.
Trading pattern
Trade from max range with autos and use (Q) to maintain spacing and avoid (E) stun.
Hold (E) for punishing Gragas's engage or for wall stuns rather than using it as poke.
Step forward to punish Gragas immediately after he misses (E) or uses (R) for displacement.
Danger windows
Respect (E) stun and (R) displacement as lethal engage tools, especially when his passive sustain is up.
Be cautious when your (E) is down or after pushing without vision, as Gragas can punish with short trades or jungle assistance.
Avoid fighting near walls if you cannot control spacing, as Gragas can capitalize on your positioning with (E) and (R).
Early game
Keep the wave on your side to limit Gragas's ability to engage with (E).
Avoid pushing without vision to reduce vulnerability to Gragas's short trades and jungle ganks.
Use (E) to punish Gragas when he attempts to engage or overextend early trades.
Power spikes
At level 6, use (R) for stealth repositioning to outplay Gragas's engage and extend trades.
After two core items, pressure side lanes aggressively with (W) true damage to shred Gragas's durability.
Respect Gragas's level 6 (R) displacement and avoid committing when it is available to prevent being isolated or knocked into his team.
Win conditions
Use ranged poke and (Q) stealth repositioning to deny Gragas safe trades and scale safely.
Exploit missed (E) cooldowns by stepping forward to apply pressure and zone Gragas from farm.
Reach your two-item power spike to dominate side-lane duels and kite Gragas effectively, forcing him to rely on team collapses rather than isolated fights.
Tip: For Vayne vs Gragas, read overview, trading pattern, and danger windows first for a fast Top lane check.