Malphite vs Jayce Top Matchup
Malphite Top wins 57.1% of 3,664 Low Elo games against Jayce Top, +2.4 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.
Why Malphite is favored
Malphite's armor blunts much of Jayce's physical damage, and Jayce's mains describe Malphite's R as a constant kill and teamfight threat. Jayce can still use Hammer Stance(E) to create space, but must avoid giving Malphite a clean engage.
Measured in High Elo: Malphite wins 2.7pp more often than expected over 3,016 games.
How to play as Malphite
Look for R after Jayce has spent Hammer Stance(E) to knock you away; the engage is more reliable once his close-range disengage is gone.
Jayce's ranged attacks and Hammer Stance(Q) deal physical damage, while Malphite's armor-heavy build and armor-scaling E reduce the value of that damage.
Jayce's Thundering Blow(E) can knock Malphite away from close range, while Malphite's R can punish Jayce if he spends that disengage first.
How to play as Jayce
Use Hammer Stance(E) to push Malphite away, then retreat with Acceleration Gate(E); track his R and avoid extending trades when it is ready.
Sources
These notes come from r/jaycemains, checked against the champions' abilities.