At the start of 2018, Lambert replaced Mark Hughes in the Potters dugout and the Scot has since guided the club to five points from four matches in the Premier League.
Lambert has praised the work-rate of his first-team squad since his arrival, leading to the new head coach to claim that his players must have shown complacency during the first half of the campaign.
At a press conference, the 48-year-old told reporters: "From the start of the season, I don't think anybody would have visualised the football club to be in the position it was in.
"But sometimes you are, and you can sleepwalk into things. I think that's what has happened here. The lads need everybody. They need a little bit of help from their teammates and, if that happens, that will transpire right through the club."
Stoke make the short trip to the East Midlands to face Leicester City on Saturday.