That is the view of Arsenal legend Paul Merson.
Arsenal have been rocked by the news that Sanchez wants to quit the club, with the Chile star determined to win the Champions League for the first time in his career.
Despite winning prestigious prizes at Barcelona, he failed to lift the trophy during his three years at the Nou Camp.
Manchester City are determined to snap him up, with Pep Guardiola hellbent on signing the 28-year-old after previously landing him at Barcelona.
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Sergio Aguero is better than Alexis Sanchez
Arsenal legend Paul Merson
Aguero, meanwhile, looks set to stay at City despite being tipped for an exit earlier this year.
The form of Gabriel Jesus initially thrust him down the pecking order but the Argentinean bounced back to fire Guardiola's side to a third-placed Premier League finish.
Yet, despite his rejuvenation, Merson thinks Aguero would be the perfect fit for Arsenal and his former club should demand him in any negotiations with City.
"I don't think Arsenal can replace Sanchez, can they?" Merson told Goal. "He gets 30 of their goals, but you've got to move on.
Arsenal could lose Alexis Sanchez, who is wanted by Manchester City
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Paul Merson thinks Sergio Aguero is better than Arsenal star Alexis Sanchez
"If someone doesn't want to be at the club, Arsenal are a big club and you don't want players who don't want to be there. Arsenal are a big club, a very big club and you don't want that.
"He's a good player – if I were Arsenal I'd be ringing up Man City and saying 'Give us Aguero and you can have Sanchez.'
"[If Alexis wants to go to Man City] then I'd say I want Aguero. He's better than Sanchez."