Cristiano Ronaldo hasn’t had many tough weeks during his incredible career but this is one of them.He was helpless as Juventus were knocked out of the Champions League by Porto on Tuesday.We say ‘helpless’ but he really could have helped his side if he hadn’t turned his back and jumped in the wall as he faced Sergio Oliveira’s extra-time free-kick.It resulted in a goal - one that Juve couldn’t recover from.While Ronaldo will feel he could have done much better in the wall, the criticism has perhaps been a bit over the top.

The Italian media suggested he had “betrayed” Juventus, Fabio Capello called it an “unforgivable mistake”, former Juve striker Nicola Amoruso suggested he is “afraid of receiving a ball in the face because he cares about his image”, while another ex-player Alessio Tacchinardi has now said that Ronaldo needs to apologise for not speaking up.

"He (Ronaldo) was rested in last weekend's game against Lazio, so what was he doing against Porto?" Tacchinardi told TWM Radio.

"Federico Chiesa went to talk on TV, but I would have expected Ronaldo to do so. He has to make an apology to the supporters."

But now, Ronaldo has spoken up in the form of an Instagram post.

Ahead of Juve’s huge Serie A clash against Cagliari on Sunday evening, Ronaldo wrote a rather inspirational message accompanying a picture of him working hard in training.

It read: “More important than the number of falls you take in life, is how fast and how strong you get back on your feet... True champions never break! Our focus is already in Cagliari, in the Serie A struggle, in the Italian Cup final and in everything that we can still achieve this season.

“It’s true that the past belongs in museums (I should say!), but fortunately, football has memory... and so do I! History can’t be deleted, it’s written every single day with resilience, team spirit, persistence and lots of hard work. And those who don’t understand this, will never achieve glory and success.”

Fighting talk from the five-time Ballon d’Or winner.

However, it’ll take a massive effort to turn their league campaign around.

The Old Lady are currently 10 points behind league leaders Inter Milan although they do have a game in hand.

Ronaldo really will need to be at his very best from now until the end of the season if Juve are to make it 10 Serie A titles in a row.