The Haupt Racing team driver started seventh and ran fifth in the early stages before a safety car was called when David Schumacher tipped three-time champion Rene Rast into the gravel at the final corner.
This coincided with the pit window opening on lap seven, and a quick turnaround from his team when the pack poured into the pits meant Stolz rejoined in the net lead over poleman Sheldon van der Linde.
