Now with China's Shandong Luneng, Fellaini announced his international retirement last week.
"We now have to think back to some of the best moments Marouane has given us," says Martínez.
"The way Marouane always focused on the field must be a source of inspiration for our younger generations. This is how you represent the Red Devils."
Fellaini retires with 87 caps and 18 goals.