Anti-Mage + Nyx Assassin

Why this works

Having Nyx Assassin on the team creates the map control that a farming Anti-Mage craves. Nyx is constantly hunting from the early game with Vendetta, forcing enemies to play defensively and burn resources on vision. This pressure naturally gives Anti-Mage the space he needs to secure his core items on schedule. Their kits also combine to drain the enemy's resources. The constant mana loss from both Mana Break and Mana Burn makes it incredibly hard for opponents to cast spells, which directly empowers Anti-Mage's Mana Void for easy kills.

The typical game involves Nyx Assassin making plays across the map while Anti-Mage splits the push and farms. Enemies have to choose between grouping up to stop the split push, which leaves them vulnerable to Nyx's initiation, or spreading out to farm and getting picked off. Once Anti-Mage is ready to fight, Nyx provides excellent lockdown with his stuns, holding a target in place for AM to Blink on and finish off. This forces the opponent into a reactive game, which is a tough spot to be in against a carry who scales like Anti-Mage.