The Uzbek-born billionaire, who failed with a recent bid to buy out Stan Kroenke, has a 30 per cent stake in the club but no seat on the board.
After months of speculation the Gunners finally confirmed the club had reached an agreement with Wenger to extend his stay at the Emirates for another two years.
Despite guiding Arsenal to a record 13th FA Cup with victory over Chelsea on Saturday, the decision to hand the Frenchman a new contract has not gone down well with some fans.
But Usmanov insists the club must get behind Wenger in order to make sure his legacy is not tarnished.
Alisher Usmanov is pleased Arsene Wenger has signed a new deal Who Arsene Wenger could axe and who he could sign in Arsenal revamp Wed, May 31, 2017
Arsene Wenger has signed a new two-year deal with Arsenal but who could he sign and who could he axe in a mass overhaul at the Emirates?
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He has a great opportunity to deliver the success that the fans deserve and the legacy that his long contribution merits.
Usmanov said: "I am pleased that Arsene Wenger will continue to manage Arsenal for the next two years as he is one of the very best coaches in Europe.
"What is now of paramount importance is that he receives the full support of the Board and majority shareholder.
"He has a great opportunity to deliver the success that the fans deserve and the legacy that his long contribution merits.
"However without the right support there remains a real risk that his legacy will be tarnished.
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Arsene Wenger signed a new two-year deal with Arsenal today
"If the support is not forthcoming, we stand ready to step in and do everything we can to deliver success on and off the field."
Kroenke added: "Our ambition is to win the Premier League and other major trophies in Europe.
"It's what the fans, players, staff, manager and board expect and we won't rest until that is achieved. Arsene is the best person to help us make that happen."