The duo joined the Old Trafford club this summer and have now been given shirt numbers.
Martinez, whose £55million transfer from Ajax was completed earlier this week, takes up the No 6 shirt at Old Trafford. The shirt number was vacated by Paul Pogba, who has moved back to Juventus. The likes of Gary Pallister, Jaap Stam and Wes Brown have also worn the No 6 shirt at United in the past couple of decades.
Fellow new signing Eriksen who joined from Brentford will wear the number 14 shirt that was formerly worn by Jesse Lingard. Javier Hernandez and Alan Smith are the famous names that have won the shirt at United.
Eriksen and Martinez featured in Manchester United’s 4-1 win against National League club Wrexham in mid-week. Eriksen was on the scoresheet in the game, which was his first since signing for the club.
Both players can expect to receive further game time this weekend as United play Atletico Madrid in Oslo on Saturday and then Rayo Vallecano at Old Trafford on Sunday.
Meanwhile, Martinez is reunited with new United manager Erik ten Hag after they worked together at Ajax.
The Argentine joined Ajax as a defensive midfielder, but Ten Hag converted him to a centre-back during his time there.;
He admits that he offers United options in several positions.
He said: “I was with him for three years at Ajax and I know his style of playing. With him, I improved a lot, to be honest.
“He’s here in Manchester now, so again the opportunity was there and for sure he’s very important in my career.”