The striker left Old Trafford as a free agent following nine years in the Premier League during which he struggled with various injuries and loss of form.
His last appearance for United came on December 9, 2023 ahead of a free transfer to the Greek side nine months later.
Martial's fitness has improved since he completed his move as the striker yet to miss a match for his new club because of injury.
In comparison, the 29-year-old missed 92 matches for United during his stint at the club as per statistics from Transfermarkt.
The Frenchman made his 17th straight appearance for AEK on Saturday and emerged as their hero in a 1-0 win over Panetolikos FC.
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He found the back of the net during the early stages of the second half after a neat, flowing move with teammate Orbelin Pineda.
Martial's goal was his seventh of the season and has helped keep AEK in the Super League Greece title race.
They are only three points behind leaders Olympiakos, although the Olympiakos have a game in hand.
The two sides clash in their penultimate league match of the regular season before the play-offs that decide European qualification.
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Martial could therefore be on course to guide AEK to continental football for next season.
He is the club's second-highest scorer this season behind Levi Garcia and four goals off his tally from his last two seasons at United.
Despite his injury issues at Old Trafford, his seven goals match the tally of United's current leading striker Rasmus Hojlund.
Joshua Zirkzee remains on four for the campaign too, with quality in front of goal lacking in their attack.
This has contributed to their poor season as they lie 13th in the Premier League after 22 matches.
A defeat to Fulham on Sunday would be their 11th in the league and see their hopes of European qualification take another hit.