United chose not to renew Martial's contract last summer, ending his nine-year spell marked by 90 goals and persistent injury struggles.
Meanwhile, Erik ten Hag and Ruben Amorim have struggled to inspire United’s attack, with Rasmus Hojlund and Joshua Zirkzee netting just five Premier League goals combined this season.
Martial’s resurgence highlights United’s ongoing issues in front of goal, contributing to their disappointing 13th-place standing.
Zirkzee, brought in to replace Martial, has only managed three league goals, while Hojlund has added two.
United’s lack of firepower continues to be a major factor in their poor performances this campaign.
Meanwhile, Martial has scored nine goals and made two assists in 19 games and 15 starts for AEK, as they launch a title challenge against Olympiacos.