Queens Park Rangers are due to face Milton Keynes Dons on Saturday.
The R’s have picked up two very positive results in quick succession - after drawing with Sheffield Wednesday at Hillsborough and then beating Birmingham City last weekend.
However, Hasselbaink is eager for his players not to get carried away with their recent successes.
QPR take on struggling Milton Keynes Dons at the weekend, but the Dutch boss insists that he side will be punished if they start to get complacent.
"After Saturday’s win you have to be happy about the performance – but that also brings danger," Hasselbaink said.
“We cannot be too lax and be thinking we are a team that just turns up and turns it on. We have to be focused and build on our performance, and try to become a good team by producing that kind of performance week in, week out.
“To be dominant against MK Dons we will have to be properly on our game because they can keep the ball for long spells as well. It would be a pity to not go there and play with the same intensity as we did in the last game.”
QPR actually started slowly under Hasselbaink, and they have still won just three of his first 15 matches at the helm.
However, their performances have been highly encouraging of late - and clear progress has been made.
QPR are now in 11th place in the Championship table, and a few of the London club’s players have begun discussing the possibility of making a late surge for the play offs in the media.
At the moment QPR are 11 points back from the top six, but if they can pick up a victory at stadium:mk, they could reduce that deficit to single figures.