And Hartley was delighted the three points moved the Tayside outfit into sixth place in the Premiership.
The Dark Blues now face Motherwell on Saturday and the Dens gaffer is determined the team will meet the Fir Park challenge.
“The players need to know this is not a one-off.
“It will be hard work again in training. The challenge for us is that can’t be a one-off because it was Rangers.
“We have to be like that every time.
“The league is so tight, with everybody jostling to get in there, that we will be looking over our shoulders.”