The goalkeeper has starred alongside the Barcelona man for Argentina and claims he marveled at Martial's talent during a loan spell with Monaco
Anthony Martial's ball control has been likened to Lionel Messi's by Manchester United team-mate Sergio Romero.
Romero has played alongside Messi, a five time Ballon d'Or winner, for Argentina and started the 2014 World Cup final against Germany in Brazil.
He was signed by the Red Devils from Sampdoria in July 2015, but had a loan spell at Martial's former club Monaco in 2013-14.
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The goalkeeper told United's official website : "He really is one of the best I’ve seen.