Ekko vs Trundle

Throw Timewinder (Q) at a champion, then position so the device passes through them again on its way back: it expands into a slowing field, and the return hits again.

Hit with Timewinder (Q) out and back, and weave in the empowered auto from Phase Dive (E): the third hit triggers Z-Drive Resonance (passive), with bonus damage and speed.

Cast Parallel Convergence (W) where the fight will happen, then step into the sphere when it appears: you stun the enemies inside and gain a shield.

Engage, deal your damage, then cast Chronobreak (R): you return to where you were 4 seconds earlier, in stasis, and recover health based on what you lost.

Don't fight in Frozen Domain (W): he gains move speed, attack speed and increased healing inside. Back off to draw him out of the zone.

If you deal physical damage, back off after his Chomp (Q): it steals some of your attack damage for a few seconds, and he gains it.

Get away from Pillar of Ice (E) as fast as you can: it slows nearby enemies and blocks the path while it stands.

Back off when he casts Subjugate (R) on you: he steals part of your armor and magic resist, and gains what you lose.