The Premier League outfit were able to reach the Europa Conference League semi-finals with a dramatic victory over the Ligue 1 side in France on Thursday night.
Lille overturned a 2-1 first leg deficit to lead 3-2 on aggregate with four minutes remaining, only for Matty Cash to level the tie and Villa to eventually prevail 4-3 from the spot.
However, the conclusion to the match was packed with drama, Martinez taking centre stage to save penalties from Nabil Bentaleb and Benjamin Andre to send his team through to the last four.
What did Martinez do?
In the first half, Martinez had received a yellow card for perceived time-wasting, and the referee was in constant dialogue with him at the start of the shootout, naturally wary of a repeat of his antics for Argentina against France in the 2022 World Cup final.
Coincidentally, the stopper had been jeered throughout the contest for the same reason, and it appeared that he had pushed his luck too far when gesturing to the crowd after saving Lille's first penalty.
The referee dished out another caution to Martinez, the belief being that he would be prevented from remaining between the sticks for the penalties that would follow.
Unbeknownst to the majority, yellow cards received during the match are not carried away into a penalty shootout, subsequently allowing the 31-year-old to continue.
What did Emery say?
Emery initially heaped praise on his number one, talking up his importance to the team, but the Spaniard also acknowledged that he was expecting to have to call upon one of his outfield players to deputise.
As quoted by Birmingham Live, Emery said: ""He is very important for us. He has his personality and his personality in the dressing room is very important because he is a leader with his experiences. He has a really brilliant mentality.
"And then 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. I am very proud of all the players."
He added: "Yes (I thought he had been sent off). But the rules are like that. Yesterday you [the media] were all asking about me about the reception he 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."
What next for Villa?
Villa will now square off against Olympiacos in the semi-finals after the Greek team edged out Fenerbahce, also in a penalty shootout.
Emery's initial focus will be on facing Bournemouth in the Premier League on Sunday, Villa attempting to secure the win that will bolster their hopes of finishing in the top four of the standings.