Robles, who joined the Latics on loan until the end of the season from Atletico Madrid last week, impressed in a hard-fought match against the non-league side as Wigan triumphed 1-0.
The 22-year-old Spaniard will now compete with Ali Al Habsi and Mike Pollitt for a regular starting berth.
Martinez said: "I thought he did really well. It doesn't get more challenging maybe than making your debut in the FA Cup fourth round away from home.
"I thought he was superb. He didn't get caught by the event. He communicated well and his decision-making and distribution was outstanding.
"I think we saw a couple of flashes of the phenomenal goalkeeper that he is and we are delighted to give him this sort of welcome to the English game."
Robles made 13 appearances last season during a loan spell with Rayo Vallecano as well as featuring twice for Atletico.