Prioritize controlling jungle tempo to avoid Rek'Sai's early aggressive invades and ganks given her very high early pressure and mobility.
Focus on safe farming and timely objective control to reach your stronger late-game dueling and splitpush potential against Rek'Sai's early snowball attempt.
Jungle Plan
Start with a full clear then path to Scuttle Crab if lanes can assist, securing river control against Rek'Sai's early tempo.
Look for invade opportunities only after tracking Rek'Sai's pathing and confirming she is on the opposite side of the map.
Prioritize dragon and Rift Herald setups when Rek'Sai is visible elsewhere or after successful counter-ganks to deny her tempo.
Danger windows
Rek'Sai's early three-camp clear into level 3 invade is a high-risk window; avoid isolated jungle fights before level 4.
Isolated river Scuttle fights without lane priority are dangerous due to Rek'Sai's tunnel collapse potential.
Low-health clears or forced smite fights near objectives are risky since Rek'Sai's knockup and execute chase can punish mistakes.
Early game
Opt for a full clear to reach level 4 quickly and avoid Rek'Sai's level 3 three-camp invade attempts.
Contest first Scuttle Crab only if nearby lanes have priority and vision to reduce risk of counter-ganks.
Avoid isolated river fights early as Rek'Sai's tunnels and knockup make her dangerous in 1v1 or 2v2 skirmishes.
Power spikes
Level 6 unlocks (R) death denial, allowing you to commit to extended fights Rek'Sai can't easily punish.
Two-item spikes greatly increase crit damage and mobility, enabling side-lane pressure that forces Rek'Sai to respond.
High Fury stacks boost trade threat and sustain, letting you punish Rek'Sai after she uses tunnels aggressively or her knockup is down.
Win conditions
Convert your scaling advantage by pressuring side lanes after two items, forcing Rek'Sai to answer and opening map objectives.
Use vision and lane priority to track Rek'Sai's movements, enabling safe counter-jungling and objective setups.
Leverage (R) to win extended duels and secure dragons or Rift Heralds, denying Rek'Sai's early tempo and snowball potential.
Tip: For Tryndamere vs Rek'Sai, read overview, trading pattern, and danger windows first for a fast Jungle lane check.