Cristiano Ronaldo reportedly left ​Juventus Stadium before the final whistle as he was annoyed at being substituted in his team's ​1-0 win over AC Milan.

The Portuguese superstar was taken off by Maurizio Sarri as he was ineffective, with his team going on to beat ​Milan 1-0 to regain their place at the top of ​Serie A.

It was the second game in a row in which he had been substituted, and as he left the pitch, the 34-year-old stormed past Sarri and straight down the tunnel.

​Sky Sports Italia reported that the 34-year-old was 'irritated' at being taken off and left the stadium before the end. Ronaldo again struggled because of a lingering knee injury and was replaced by Paulo Dybala - who went on to score the winner.

As he walked past Sarri, the Portuguese forward muttered something to the former Chelsea boss before walking straight down the tunnel. However, the Italian said he did not know whether Ronaldo had left the stadium early.

“Disrespectful to his teammates? Like I said, I don’t know. If it’s true that he left before the end it is a problem to be resolved with his teammates,” he said, as per ​Goal.

“I have no problem with Cristiano, he should be thanked because he made himself available despite not being in the best condition. In the last month he has had discomfort in his knee and this is a little problem for him,the former ​Chelsea and ​Napoli head coach added.

Ronaldo had ​reacted furiously after being substituted in his team’s 2-1 win against Lokomotiv Moscow as well, in a match that saw Juventus advance to the ​Champions League round of 16.

“The important thing is that he made himself available. If he gets angry when he comes out this is part of the game. It’s only natural a player is going to be irritated about leaving the pitch, especially when he worked so hard to be there," continued the Juventus coach.

“All players who are trying to give their best will have at least five minutes of being annoyed when they are substituted, but a coach would, in general, be much more worried if he didn’t seem upset.”