Originally Posted by Stosstruppen

"The most important battle for the tank was at Cambrai"

And the Germans subsequently retook the lost ground with infantry, spearheaded by assault troops using infiltration tactics.

Plus, you have to remember that most WW1 tank's armor were really only "proofed" against rifle fire. They just needed a way to overcome the withering fire of machineguns during the attack and most weren't armored more than 12mm. Direct hits from field artillery of any caliber was catastrophic, and by the end of the war the Germans had become well versed in knocking out tanks both with field artillery and Mauser 13.2mm Tank Abwehr Gewehr rifles. However, when these weapons weren't readily available the german infantry had little defense against tanks except concentrated charges of stick grenades. The design and role of WW1 tanks wasn't a novelty, but it was still in it's early stages of evolution, as were the means to combat them.