During the shootout, Martinez - who had been booked earlier for time-wasting - was shown another yellow card for appearing to gesture to home fans. But he was able to continue as the initial yellow card doesn't carry into the shootout. The Argentine saved twice as Villa won 4-3 on penalties.
Asked if he feared his goalkeeper was being sent off, Emery replied: "Yes. He is very important for us.
"On the pitch he has his personality and he played fantastic. He saved two penalty shots so of course I am very proud of him.
"Yesterday you (the media) were all asking me about the reception he (Martinez) will get here in France and you could see it throughout the game.
"He is very experienced and he was trying to control his emotions but the supporters were pushing him. I believe in him and he is mature but with personality. He is always under his own control."