Rek'Sai must leverage her very high early game pressure and gank threat to disrupt Master Yi's slower scaling and farming jungle style.
Use Rek'Sai's fast clear speed and high invade resistance to control river scuttle and contest early objectives before Master Yi hits his power spikes.
Jungle Plan
Use tunnel paths to repeatedly gank flashless or overextended lanes, snowballing Rek'Sai's early lead before Master Yi can scale.
Invade Master Yi's jungle early to disrupt his farm and force him into unfavorable fights before his item spikes.
Control dragon and Rift Herald vision to force Master Yi into contested objective fights where Rek'Sai's CC and early dueling excel.
Danger windows
Avoid isolated river fights early where Master Yi can use (Q) untargetability and (W) damage reduction to outlast Rek'Sai's burst.
Be cautious during forced smite fights if Rek'Sai's cooldowns or health are low, as Master Yi's resets and sustain can turn fights.
Respect the scaling window post-Master Yi's first item completion where his dueling and objective control improve significantly.
Early game
Start with a three-camp clear into an early invade or counter-invade to capitalize on Rek'Sai's strong level 3 presence.
Prioritize early river control and contest first Scuttle only if nearby lanes have priority to avoid risky isolated fights.
Avoid extended early fights if Master Yi is nearby without lane support, as his sustain and resets become dangerous post-level 6.
Power spikes
Rek'Sai's level 3 power spike enables strong early ganks and invades; use (W) knockup and tunnels to secure kills or force summoners.
Respect Master Yi's level 6 (R) spike which unlocks reset potential and chase power; avoid fighting him without prior CC commitment.
Rek'Sai's early item power allows her to contest objectives and duel effectively before Master Yi completes his first major item.
Win conditions
Convert early tunnel ganks and successful invades into dragon and Rift Herald control to snowball Rek'Sai's lead.
Deny Master Yi free farm by invading and counter-jungling before he reaches key item spikes.
Use Rek'Sai's superior early dueling and CC to force fights before Master Yi can safely enter with resets, securing kills and objectives to close the game early.
Tip: For Rek'Sai vs Master Yi, read overview, trading pattern, and danger windows first for a fast Jungle lane check.