Cristiano Ronaldo given new nickname by Manchester United teammate Lisandro Martinez

Manchester United defender Lisandro Martinez has appeared to reveal his nickname for Cristiano Ronaldo after commenting on one of the Portuguese star's Instagram posts.

Martinez has quickly become a fan-favourite at Old Trafford after arriving at the club from Ajax in the summer - with the centre-back playing an important role in the Reds' recent turnaround in form.

United have won their last four successive matches in the Premier League, with Diogo Dalot, Martinez, Raphael Varane and Tyrell Malacia forming a much-improved defensive backline in recent weeks.

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The Argentine defender appears to have a strong relationship with all of his teammates - and he has already created a bond with 37-year-old Ronaldo.

Ronaldo posted a picture to his Instagram account of him in action during the win over Southampton. As expected, a number of people commented on the post, including Martinez.

Martinez wrote: "El bichoooo", which translates to, "The Bug" in English. It remains to be seen why the United defender refers to his teammate as 'the bug', but it appears the duo have sparked a strong friendship in recent months.

Martinez recently suggested that the Reds will need Ronaldo's goals again as Erik ten Hag's side continue to improve after a difficult start to the season.

"We know how big Cristiano Ronaldo’s goals are," said the defender. "It’s very important that he scored for his confidence and for the team."

Ten Hag also praised Ronaldo after he scored his first goal of the season against Sheriff in the Europa League in midweek, insisting that the veteran striker 'totally committed to the project' at Old Trafford.

The Dutchman said: "I