Riven vs Mordekaiser Top Matchup

Riven Top wins 44.7% of 1,202 Low Elo games against Mordekaiser Top, -0.8 points vs expected, 2-patch window 26.19-26.20.

Researched on LoL patch 26.20. Tips are written to hold at any rank; stats come from Low Elo ranked games up to patch 26.20.

How to play as Riven

Keep a minion between you and Mordekaiser when you can, and use Broken Wings(Q) movement to dodge Obliterate(Q) rather than taking its isolated hit.

Save Valor(E) to dodge Death's Grasp(E), then take a short trade when his Q and E are down; avoid extending into his passive damage aura.

Obliterate(Q) deals increased damage when it hits only one target, so a minion near Riven removes that isolated-target bonus if the Q also hits the minion.

Sources

These notes come from r/Rivenmains, checked against the champions' abilities.