I'm sorry but this message seems to have escaped our attention. Thank you, Kennedy, for reviving it.
First of all, the Greek is wrong. "Διαγωνισμός γνώσεων" is a knowledge quiz. What is probably meant here is "η μάχη για τη γνώση" (the fight for knowledge) or "ο ανταγωνισμός των γνώσεων" (the contest for knowledge).
Then it should be followed by "θα μας σκοτώσει όλους" (will kill us all) or, more colloquially, "θα μας πεθάνει όλους" (will be the death of us all).
After all this, you don't expect us to provide a source, do you? Though I faintly remember that, when I was quizmaster for Who Wants To Be A Millionaire, I often used to say to my dear colleagues "Αυτός ο διαγωνισμός γνώσεων θα μας πεθάνει όλους" (This quiz game will be the death of us all). With WWTBAM off our screens, I can now say "This forum will be the death of us all".