Under-fire Manchester United veteran Wayne Rooney has won the backing of Arsenal boss Arsene Wenger, who said ‘big players’ do learn from their mistakes.

He was commenting to journalists at the Gunners’ weekly press conference at the team’s training base in London Colney, near St Albans, ahead of the Premier League match with Manchester United on Saturday (19).

Wayne Rooney hit the headlines for his celebrations after England’s 3-0 win over Scotland, with allegations that he appeared to have been drinking.

He recently apologised to interim England manager Gareth Southgate in the wake of the furore, admitting images of him at a wedding at the team’s hotel were ‘inappropriate’.

Asked today (Thursday) for his advice to young players on how to behave in their downtime, Wenger replied: “Just to follow instructions of their managers and their coaches.”

In the wake of Wayne Rooney’s apology this week, a journalist added: “I want to ask a question about players’ behaviour, and their relationship with alcohol.

In the last 20 years, do you feel it is less of a culture than it was?”

Wenger replied: “Yes of course,”

Pressed further, he told the journalist: “Look, we have all been young – I think you as well – overall, I believe that it is part of being a youth [it is normal] to make mistakes, and after that, analyse well and make an assessment.

“All the big players make mistakes, but after that, they make a good assessment of the situation, and react in a positive way.”

In team news, the fitness levels of Arsenal forward Alexis Sanchez are causing no concern for the Gunners’ boss as he told reporters that while he had not “heard a lot” from the footballer, he had texted the club after playing overseas to say he was in “good shape”.

The Chile forward scored twice in his country’s World Cup qualifying win over Uruguay (3-1), and there have been fears he could miss Saturday’s clash.

Wenger said: “I will see him tomorrow morning and we will see if he can be involved in the squad or not.”

However, Hector Bellerin is out for four weeks, with Wenger saying that he was injured in the last 10 seconds against Spurs, “and Cazorla is out, for exactly how long, I don’t know”.

Wenger said that Arsenal now goes “into a period of big games, one after the other, and the way we do these big games … overall I believe we are on a very strong run - 16 unbeaten games.“

Asked about Alexis playing overseas, and what he thought of his decision to do so, a supportive Wenger said that he understood the “importance of Chile qualifying for the World Cup.

“I understand that Alexis is keen to play for his country, and in such an important game.”

When informed that Arsenal’s international players have flown further than Manchester United international players, and asked whether that could have an impact on Saturday’s game, Wenger replied: “I don’t think so, I don’t think a few miles will stop them playing well.”

Asked how he would describe his current ‘relationship’ with Jose Mourinho, he replied: “I don’t think I need to describe our relationship”, adding that the most important aspect of the game was how the teams played.

He confirmed he would ‘of course’ shake his opponent’s hand, as “I respect the ritual that is so important in the Premier League”.

Wenger said it was not a competition between two managers, but a contest between two teams. And while he could ‘understand’ people wanting controversy, it was important to realise that it was the match itself that would be of interest - and watched - around the world, thus it was the quality of the game on the pitch that was more important.

He refused to speculate on the potential impact of Manchester United being devoid of some key players through injury or, in the case of Zlatan Ibrahimovic, suspended after recently receiving his fifth yellow card of the season.

Wenger pointed that he, too, had injured players and refused to comment on any possible weaknesses in the Man United squad.

• Manchester United V Arsenal, Old Trafford, Saturday November 19, 12.30pm