London - Arsenal's second largest shareholder Alisher Usmanov has warned Arsene Wenger to start learning from his mistakes as the pressure mounts on the Gunners' boss.
The Gunners have lifted just one trophy in nine-and-a-half years and a 2-1 defeat at home to Manchester United on Saturday marked the team's worst start to a season since 1982.
And Usmanov, who owns 30 percent of the Premier League club, believes Wenger is letting his purist footballing principles stand in the way of Arsenal's success.
"Arsene Wenger is one of the greatest coaches, not just of European, but of world football," Usmanov told CNBC on Monday.
"But we have a Russian proverb which goes: 'even an old lady can have a roof falling on her'.
"Everybody makes mistakes. He can make mistakes and I know as you age it is more difficult, more challenging to accept one's mistakes.
"The potential of the team is there but there is no critical evaluation of mistakes and they need to acknowledge them.
"Because no genius can retain the same level of genius if they do not acknowledge mistakes.
"It's only when you admit your mistakes that you can get rid of them. I wish this to my club.
"Nothing bad is happening apart from repeating the same high result -- we keep being in the middle of the Champions League but we only lose the first knock-out games.
"Some may be happy with that but as a shareholder, I am not."
Wenger's position as manager has come under intense scrutiny in recent seasons as the team has drifted further away from a serious challenge in either the Premier League or the Champions League.
Usmanov, who has not been offered a place on the Arsenal board, admits it is "frustrating" to be excluded from discussing the manager's future but suggested he still supports the Frenchman, adding "the club leadership relies on Wenger".
Despite spending big money on Mesut Ozil and Alexis Sanchez over the last two seasons, Wenger is no closer to turning Arsenal into title contenders, but Usmanov says the club must continue to splash the cash.
"My opinion -- and I tell it openly -- we need to strengthen every position to play on the level of such teams in the UK as Chelsea and Manchester City, in Europe like Real Madrid, Barcelona, Paris Saint-Germain and other clubs," he added.
Usmanov's comments will increase the scrutiny on Wenger, who cannot use France striker Olivier Giroud in his team's crucial final two Champions League Group D fixtures.
Giroud returned from an ankle injury earlier than expected and scored on his comeback in Saturday's 2-1 defeat against Manchester United.
But he was not expected to return until January, after all the group fixtures had taken place, and so was left out of Arsenal's original squad list.
Clubs can only register 25 players on an 'A List' for the Champions League group matches, which must be submitted by September 2 and include eight home-grown players.
Arsenal need just one point from their remaining two games to qualify for the knock-out stages and Giroud could be included for the rest of the competition, with the next squad list due by February 3.
Wenger's side, who are five points off top spot, host group leaders Borussia Dortmund on Wednesday before finishing with a trip to Galatasaray in December.