A 3-2 home defeat to Mainz on Saturday has left the northern Germany club just two points above the bottom three, while it was already their fifth defeat of the season at the HSV-Arena.
"That's the reality, just look at the points," said Van Marwijk post-match.
"The players have got to be aware that we need to put as many points in the bank as will be sufficient as quickly as possible."
When Van Marwijk took over from Thorsten Fink after six games of the season, Hamburg were admittedly two positions worse off, down in 16th position.
However, in his 10 games in charge, the Dutchman has managed to pick up only 12 points compared to the four in six games under his predecessor, indicating that the change in coach has hardly led to the desired reaction.
"I'm not one who gives up, though," added a defiant Van Marwijk. "Situations like these actually give me more energy."
He is going to need it as Hamburg face the reality of a third successive relegation campaign when they started the season with the perennial hope and expectation of qualifying for Europe.