Kylian Mbappe appears to call Cristiano Ronaldo the 'GOAT'

Kylian Mbappe was accused of calling Cristiano Ronaldo the greatest player of all time, after leaving a comment on the Portugal star's comment.

Ronaldo and his fellow Portugal stars were knocked out of the World Cup by Morocco on Saturday afternoon, as the victors became the first African side to reach the World Cup semi-finals.

Fernando Santos once again left the five time Ballon d'Or winner on the bench to start the game, as he had done in the last 16.

Unlike the first knockout round, against Switzerland, it wasn't as effective, and he had to bring Ronaldo on early in the second half.

The 37-year-old wasn't able to have an impact on the game, and Morocco held on to their one goal advantage, despite having a man sent off late on.

It left Ronaldo down in the dumps, as he was spotted in tears in the tunnel after the game, having failed to score in a knockout game in a World Cup for the fifth tournament in-a-row.

On Sunday, the former Manchester United striker took to social media to continue his emotional reaction to the game, saying winning the tournament had been his 'biggest dream.'

Of course the most followed person on Instagram is always likely to earn plenty of reactions and France star Mbappe was amongst them.

The forward posted three emojis, using the crown, high five and goat emoji to convey his feelings, suggesting Ronaldo is the greatest ever.

Of course Ronaldo's fan boys, who have been particularly vocal in the wake of his departure from Manchester United and being dropped by Portugal for the knockout stages, were all over it.

They were mostly excited by the fact the 'opinion' came from one of Lionel Messi's own PSG teammates, because obviously that's important.

Mbappe famously grew up idolising the former Real Madrid forward, and was pictured with the player's posters around his bedroom when he was 13-years-old.

His opinions on the two star forwards, who have both likely be playing in their final World Cup in Qatar, has changed somewhat in recent years.

Asked who he preferred, Mbappe came up with one of the better answers, saying, "If I had a choice between Messi and Ronaldo to play with me, I would sit on the bench and play both of them to be sure we would win."

Even that opinion came two years ago and it's likely that the former Monaco player has changed his tune since then, especially since playing with Messi.

Anyone picking Ronaldo over Mbappe on current form would need their head testing, as the current tournament has proved.

Mbappe absolutely dusted Kyle Walker during France's World Cup quarter-final victory over England on Saturday night, after the full back was expected to be the only man who could stop the 2018 World Cup winner.

His reaction to Harry Kane's missed penalty, which would have put England level and taken the game to extra time, might even go down as the defining image of the tournament, if Didier Deschamps team go on to defend their title.