Lisandro also had an offer from Arsenal, but eventually signed for United.
Bas Schothorst, one of Martinez's representatives at Essel Sports, has explained his client's thought process in the summer.
Speaking to Voetbal Primeur, Schothorst said: "[Martinez's departure] was a process of several months.
"We had contact with various top clubs and, in the end, Ten Hag's presence at United played an important role. That makes sense.
"Ten Hag knows him, has worked with him [at Ajax] and knows what he can do with Martinez. It is of course great to see that this leads to his current achievements.
"On the other hand, Arsenal is also a great club. But you have to make a choice, it is difficult."