The 54-year-old former Mexico international believes that the young forward has what it takes to still be a success in the Premier League, but that he must remain "calm"
After the arrival of former Arsenal forward Robin van Persie, United now have an embarrassment of riches up front and the 24-year-old faces some stiff competition alongside the likes of Wayne Rooney and Danny Welbeck, while Dimitar Berbatov is still at the club.
Nevertheless, Sanchez thinks that as long as the club continue to trust the the former Chivas Guadalajara man, that he still has a part to play at Old Trafford.
"They must have patience with him, he's a great player," the former Madrid man told reporters.
"Javier has a lot of quality that he will keep showing, what he needs is continuity, because when he was given that before he was effective".
"He needs to be calm and have confidence in his ability because when there is more competition the pressure can rise."