Grealish was restored to Villa’s starting line-up against the Toffees, but he was unable to influence the game, as his side fell to crushing 4-0 defeat.
The wide-man was on the periphery for much of the contest, and he never managed to show his creative streak.
And Garde admitted: "It was a difficult game for everybody. Jack is a young player he has to work like Carles [Gil], like Jordan [Ayew], like Idrissa [Gana].
"I know the team is quite young but they have a chance to show what they can do.
"Not only Jack but a few players I was wanting a little bit more from."
Everton destroyed Villa in the match, and it was a hugely concerning defeat for Garde’s side.
The Villans had improved in Garde’s first match in charge – which they drew 0-0 with Manchester City – but they appear to have gone backwards over the international break.
Everton’s Ross Barkley and Romelu Lukaku both scored braces in the fixture, and Villa were unable to deal with their attacking threat.
Garde’s side’s defeat extends their winless run to 12 matches, and they are still five points away from safety with plenty of work to be done in the weeks ahead.