This matchup is a control mage (Malzahar) versus a high-mobility scaling marksman (Vayne) where Malzahar must maintain lane pressure to deny Vayne safe scaling.
Malzahar should focus on controlling the wave and using suppression lockdown to neutralize Vayne's high early lane pressure and mobility.
Trading pattern
Push with (E) and Voidlings, then threaten short trades by zoning with (Q) silence or committing with (R) when Vayne steps forward.
Punish (Q) forward use or cooldowns on (E) by engaging with (R) suppression to lock her down.
Avoid predictable patterns; vary your trading rhythm to prevent Vayne from baiting your ultimate and exploiting your lack of mobility.
Danger windows
Vayne is most dangerous when (R) is active and (Q) stealth is available, enabling her to outplay committed all-ins.
Avoid fighting near walls where Vayne can pin you with (E) for a stun.
Be cautious after using (R) as your ultimate channel can be interrupted and you lose your main lockdown tool.
Early game
Use (E) and Voidlings to push the wave quickly and keep Vayne under tower, limiting her ability to kite and scale safely.
Avoid extended trades before level 6 as Vayne's mobility and true damage can punish Malzahar if (R) is not available.
Maintain vision to prevent ganks since Malzahar's push and predictable patterns can be exploited early.
Power spikes
At level 6, use (R) to execute reliable all-ins or picks, forcing Vayne to respect your lockdown and play cautiously.
After your first mana/AP item, increase wave pressure and trade confidence to deny Vayne safe farming.
Respect Vayne's level 6 (R) stealth repositioning and (E) wall stun by avoiding extended fights without your suppression ready.
Win conditions
Keep the wave pushed permanently with (E) and Voidlings to deny Vayne safe farm and force her under tower.
Use (R) suppression to pick Vayne when she oversteps or after her key cooldowns are used.
Transition lane pressure into objective control and teamfight presence by leveraging your lockdown and wave control to limit Vayne's scaling impact.
Tip: For Malzahar vs Vayne, read overview, trading pattern, and danger windows first for a fast Top lane check.