Making his fifth appearance but his first start for the Red Devils, Praet delivered a perfect cross to set up Michy Batshuayi for Belgium's first goal in their 2-0 win in Kazakhstan on Sunday.
"What pleases me as a coach was to see that Dennis was ready," said Martinez.
"He was desperate to be on the pitch, that's what I want to see in the players.
"He played technically, it was a pleasure to see him play. Much of the game went through him and at the end I was happy to see that he had enjoyed himself. He played extremely well."