The Red Devils, who appointed Van Gaal as manager in May, are fourth in the Premier League after a battling 2-1 victory over Everton before the international break.
However, United have managed to secure just three wins in seven Premier League outings, as well as a humiliating 4-0 loss to MK Dons in the Capital One Cup.
But Ferguson highlighted his below-par start to his United spell before becoming British football’s most-decorated manager, stressing Van Gaal needs time at United.
“He’s not been getting the results that are expected but when I came to the club I didn’t get the results I expected myself at the beginning,” Ferguson told MUTV.
“What we needed then was Sir Bobby Charlton, Martin Edwards and the board to stick by me and we had a great spell after that.
“Once I got settled into the club, everything was fine. Louis is going through that same process and there’s no doubt in my mind that he will sort it out.”
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