Portugal2 - 1Czech Republic

The 21-year-old made just his third appearance for Portugal as a 90th-minute substitute in Tuesday evening's European Championship clash with Czech Republic.

Shortly after his introduction, Conceicao scored the winner for his country, firing into the back of the net from close range to spark huge celebrations in the Portugal end.

Martinez hailed the "incredible maturity" of the Porto forward, who will hope to have worked his way into the starting side for Saturday's clash against Turkey.

"Francisco is an example of what it means to deserve to be in the team and be prepared to help the group as well," Martinez told reporters after the contest.

Conceicao proved to be the hero for Portugal

"He has incredible maturity, he has a scent for danger inside the area and he showed it. For a coach, seeing him come off the bench and show what he showed is very important."

Meanwhile, Conceicao added: "It was a tough game, I wanted to help the team score the goal we needed to start the Euro well with a win and that's what I did. I helped the team and luckily things turned out well.

"It's a tremendous joy to represent our country. My father, mother, brothers and my girlfriend, lots of people were here, so this victory is for them."

Martinez also hailed his side for showing "resilience" in their competition opener, with Portugal needing to come from behind in order to pick up all three points in the Group F contest.

Martinez delighted with his side's "resilience"

"Today it's not about assessing this game from the technical or tactical point of view," said the head coach.

"Today we won because we showed resilience, willpower and belief. It's the first time we've come from behind to win [under my tenure]. Today we believed, we showed incredible personality.

"It's a game where we had 13 corners; the Czech Republic had none. If we scored early we could have won by three or four goals. The atmosphere was incredible. Our fans did not deserve to lose this game.

"Nuno Mendes in a back three? He has the physical attributes to play in a three-man defence. It's important to have symmetry in the middle block. The Czech Republic are a physical team. The important thing is not the starting eleven, but how the game ends. We showed we had prepared well."

Portugal will tackle Turkey and Georgia in their final two group games this summer, and they have already placed themselves in a strong position to reach the knockout round of the competition.