Cristiano Ronaldo's biggest game since his Manchester United return was a disaster, as he was almost sent off and had a goal disallowed in a brutal defeat

• Cristiano Ronaldo had a nightmare Sunday in his biggest game since returning to Manchester United.
• United lost 5-0 to its arch rival, and Ronaldo's individual performance was also poor.

Cristiano Ronaldo had an afternoon from hell on Sunday as Manchester United was hammered by fierce rival Liverpool.

In a torrid outing at Old Trafford, Ronaldo was almost sent off, had a goal disallowed, and saw his team beaten 5-0 in one of English soccer's most storied rivalries.

With his team trailing 3-0 before half time, Ronaldo fought for the ball with Liverpool midfielder Curtis Jones.

Having been outmuscled, the Portuguese forward proceeded to wildly swing his leg in the air and struck Jones in the chest.

The Liverpool player fell to the floor at which point, Ronaldo angrily kicked the ball into his chest before walking away.

Ronaldo, who rejoined Manchester United this summer, was confronted by Liverpool defenders Andy Robertson and Virgil van Dijk, while his Portuguese teammate Bruno Fernandes came to defend him.

Referee Anthony Taylor showed Ronaldo a yellow card, but it could have very easily been red, with many social media users and pundits calling for his dismissal.

Ronaldo's evening only got worse from that point on.

With his team trailing 5-0, Ronaldo thought he'd scored a brilliant goal, only to have it ruled out for offside after a check from the video assistant referee (VAR).

You can watch the disallowed goal, as well as highlights from the whole game, here.

United outclassed by rampant Salah and Liverpool

The fortunes of Ronaldo and Liverpool forward Mo Salah could hardly have been different.

The Egyptian continued his stellar start to the season with a hat-trick, becoming the first opposition player ever to do so in the Premier League at Old Trafford.

It took just five minutes for Liverpool to take the lead in the league's fiercest rivalry, which United had previously dominated for two decades before Jurgen Klopp's arrival on Merseyside.

On the counter-attack, Salah played in Naby Keita who rolled the ball past goalkeeper David de Gea to open the scoring.

Eight minutes later and Liverpool had doubled its lead. This time, right back Trent Alexander-Arnold crossed the ball for Diogo Jota to finish.

Salah then struck twice before half time to give Liverpool a four-goal lead.

The league's deadliest finisher completed his hat-trick in the 50th minute.

Following Ronaldo's disallowed goal a couple of minutes after Salah's third, United's afternoon went from bad to worse on the hour mark when substitute Paul Pogba was sent off for a dangerous tackle on Keita.

The emphatic win means Liverpool remains in second, one point behind league leaders Chelsea, while United slipped to seventh by Sunday night.