Ekko vs Xin Zhao

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.

Get out of the line of the Wind Becomes Lightning (W) thrust: it slows you and marks you as Challenged, which extends the range of Audacious Charge (E) on you.

If you have CC, use it during Three Talon Strike (Q): without his three autos, there's no knock-up, and his other cooldowns don't go down.

After Audacious Charge (E), keep your distance: it's his only dash to get back on you, and without it he has to walk up to you.

After Crescent Guard (R), don't hit him from range: for a moment, he ignores damage from outside the swept zone. Back off, or hit him from inside it.

If you survive his first minutes, play for time: Xin Zhao is strongest early on, through his ganks and skirmishes.