Fans believe they know the real reason Cristiano Ronaldo cried in Portugal’s win over Slovenia.

The five-time Ballon d’Or winner wept after having a spot-kick saved by Jan Oblak in extra time, with the scored locked at 0-0.

Ronaldo subsequently went on to net the first of Portugal’s penalties in a shoot-out as Roberto Martinez’s side booked their place in their quarter-final against France.

And fans have suggested that Ronaldo burst into tears upon seeing his mother upset in the stands.

One person on Twitter claimed: “Cristiano Ronaldo saw his mother crying in the stands and completely broke down.”

“She’s not allowed now to watch big games,” Ronaldo previously joked to Piers Morgan in an interview for the Daily Mail.

“I say, ‘Listen, I don’t have a father any more. I don’t want to lose my mum, too, so you’re not going to watch the quarter finals, semi-finals, or finals.”

Elsehwere, the Al Nassr forward, who upon netting his shoot-out penalty held up his hands to the Portugal support in an apparent apology for his earlier miss, revealed to Sport TV: “Even the strongest people have their days, I was down and I was sad because the team needed me.

“Initial sadness and joy at the end, that’s what football brings, inexplicable moments, from the eighth minute to the 80th, that’s what happens.

“I could have given the national team the advantage, but I didn’t manage it, Oblak saved, I didn’t miss once during the year, and when I needed it most Oblak saved.

“It’s a feeling of sadness and joy at the same time, but the most important thing is progressing, the team deserved it.

“Slovenia spent almost the entire time defending and when it’s like that it’s very difficult, the team deserves congratulations, especially our goalkeeper who made three good saves.”

In a separate interview with RTP, Ronaldo added: “It is without a doubt my last European Championship. But I don’t get emotional about that, I get emotional about everything that football involves.

Ronaldo cried after missing a spot-kick against Slovenia (Getty)

“Because of the enthusiasm I have for the game, the enthusiasm of seeing my supporters, my family, the affection that people have for me. It’s not about leaving football, because if I do, what else would I need to do or win? It won’t be about getting one more point or one less point. Making people happy is what motivates me the most.

“We have a tough game now against France, who are one of the favourites to win.

“But we’re going to war, the team is doing well and I’ll always give my best in this shirt. I missed the penalty but I wanted to be the first to score because you have to take responsibility. I’ve never been afraid to face the usual things.”