Starting from pole position, Preining put in a faultless drive in his Porsche 911 GT3 R, surviving two safety car restarts to lead into the final 10 minutes of the race.
A victory looked certain at this stage, with his closest rival Christian Engelhart circulating three seconds behind him in the Toksport WRT Porsche.
But then a message popped up on the TV screen out of the blue, revealing that Preining had been given a long-lap penalty for a pitstop infringement.
In an instant, the Austrian’s hopes of a victory were dashed and he was forced to take the alternate lap route at 50km/h, falling to third behind Toksport WRT duo Engelhart and Tim Heinemann.
Preining looked visibly dejected during the podium ceremony afterwards, even though he had played a key role in Porsche celebrating a historic 1-2-3-4 finish at the start of the German manufacturer’s second season in the DTM.
Preining’s mood on the podium left viewers confused as to why he was penalised for the incident, with the replay of his pitstop not pointing to any obvious errors. Even the ADAC document didn’t specify the exact cause of penalty, merely stating that the Manthey EMA team had broken the pitstop rules.
Now, it has been revealed that a Manthey EMA mechanic briefly left one of the rear tyres on the floor of the pitlane before Preining’s car came in for regular service at the end of lap 17. The rules stipulate that the mechanics must hold the rear tyres once they’ve crossed the line separating the garage and the pitlane.
The intention of the rule is to ensure that tyres are not left in the pitlane, as there is a risk they could be collected by another car.
Although this offence took place on the side facing the garage, rather than near the fast lane where there is a greater chance of a rival car hitting the tyre, the stewards still deemed it as an infringement of the rules and handed Preining a long-lap penalty.
Bizarrely, the mechanic had left the tyre on the floor so he could get his fireproof overalls done up ahead of the pitstop.
"The guy went out with the tyre and realised his suit wasn't closed," team founder Olaf Manthey told Autosport's sister website Motorsport-Total.com.
"He put the tyre down, closed the suit and lifted the tyre back up. But he shouldn't have put the tyre down, he has to hold it in his hand.
"In the WEC [World Endurance Championship] you can put the tyre on the ground, but here the regulations are just different. And we have to comply with them just like the others. And if we make a mistake, then we have to answer for it. It's annoying, but it builds character."
The penalty came a day after the race director had clarified Article 39.1 of the regulations, stating that the rear tyre must not be put down after entering the working lane and must be held with muscle power. Previously, the regulations had only mentioned that the tyres must be held until the car has come to a stop.
Preining wasn’t the only driver to fall foul of this rule at Oschersleben. Maro Engel (Landgraf Mercedes), Marco Wittmann (Project 1 BMW) and David Schumacher (Winward Mercedes) were also penalised for the same offence over the weekend.
