Zandvoort DTM: New points leader Rast believes Farfus impeded him

Starting from fifth on the grid behind four BMW drivers, Rast held his position in the early laps but got bottled up behind Farfus as the top three - eventual race winner Timo Glock, Marco Wittmann and Maxime Martin - escaped out front.

While most of the field, including Farfus, took their pitstops within the first 10 laps, Rast opted to stay out until lap 18 of 37 before changing tyres, losing net positions as a result.

He then got stuck behind Paul di Resta's Mercedes for much of the latter half of the race, and ultimately slipped behind Gary Paffett to finish ninth.

The German driver did at least take the lead of the championship as a result of Audi stablemate Mattias Ekstrom not finishing.

"[BMW] had a clever strategy," Rast told Autosport.

"Three cars getting away and Augusto holding up the field.

"I was stuck behind him, everyone behind pitted and overtook me virtually.

"By the time we saw that it was too late to pit me, so I stayed out, so I lost lots of time.

"Augusto drove so slowly for the first three or four laps, [so] I said 'we need to pit now'.

"They showed me the pitboard, but that lap Augusto suddenly went two seconds quicker.

"Then I said, 'he's picked up the pace, if you still want me to pit, show me the pitboard'.

"And there was no pitboard, so I stayed out.

"I was quicker after the stop, closed up to the guys in front, but to pass is a different story, especially as being stuck in traffic destroys your tyres."

Asked if he felt BMW had asked Farfus to hold up the rest of the field, Audi motorsport boss Dieter Gass would only say: "Everyone has their own eyes."

But Gass's counterpart at BMW Jens Marquardt denied any wrongdoing on Farfus's part when asked by Autosport whether the Brazilian was acting as a spoiler.

"They all got off the line pretty well, Augusto didn't get the best of starts, and then we had to manage our pace with the tyres and this he did," Marquardt said.

"He had to manage his race, the other guys could do a quicker pace, and you could also see overtaking is really difficult here."

Rast was also pessimistic about his chances of beating the BMWs in Sunday's second race, especially with the Audi cars set to gain weight from the race pace they showed on Saturday.

"They get five kilos out, we get five kilos in, which is [worth] two or three tenths," he said. "If they don't fuck it up tomorrow, they should be P1 to P6."