The Lions, who went up from League One after winning the play-off final against Swindon at Wembley, are four points off the Championship top six after beating Leeds 3-2 on Saturday.
"We've talked from day one of pre-season about getting in the top-six," said Jackett.
"How long it would take and how we would do it was a different thing.
"It's not like we haven't discussed it or set it as a target but all season we've been working out how we can be successful this season.
"It has to be the aim. We broke it down in stages of games. We wanted to get a good start so that all the players and supporters believed."
Source: PA
