The Dutchman needed victory in Germany to qualify for the finals, to be held in Bordeaux on February 8 and 9, but a poor first round left his hopes looking slim.
De Ronde came in third place, four seconds behind Hungarian Joszef Dubrovitz to intensify the pressure on his shoulders.
But the second round was a different story as he scorched to victory 12 seconds quicker than Dubrovitz, to ensure he will be in France next month.
Frenchman Nicolas Andréani underlined domination of the vaulting class over the past two years with victory in both the compulsory routine and freestyle rounds.
In the women's event, Italian Anna Cavallaro secured victory over Switzerland's Simone Jaiser by just 0.6 points.