Reigning DTM champion Marco Wittmann says the "exciting championship" of this year is "gone" after the decision to ditch performance weights has given Audi too much of an advantage.
The 2017 DTM season has featured one of the closest title fights in the championship's history, with 10 drivers separated by 39 points heading into Saturday's first Red Bull Ring race.
Prior to the Austrian round, the series has decided to cut the controversial performance weights system from the regulations, and the opening race in Austria was dominated by Audi.
The marque swept the podium and beat the rest of the field by 21 seconds, leading BMW driver Wittmann to say the rule change has put both BMW and Mercedes on the back foot.
"It's obvious, you can see what happens," said Wittmann, who finished fifth.
"Audi profits the most and us and Mercedes are on the back foot."
Following the Saturday race, Ekstrom has extended his points lead to 28 points with Jamie Green passing Lucas Auer and Wittmann to sit second in the standings.
Wittmann said the championship could be decided among Audi drivers.
"The exciting championship we had is now gone - maybe it'll be an Audi championship in the end," he said.
"I think, we could have gotten rid [of the performance weights] after the season.
"I support the decision in general, for the sake of the sport and the fans. But I do think the timing maybe wasn't ideal."
Top Mercedes driver Auer did not echo Wittmann's complaints, saying it is not possible to calculate the effects the rule change brought.
"You cannot calculate it [the disadvantage of the current all-equal-weight situation]. Some tracks fit your car, some don't," he said.
"We'll have to see [for Hockenheim]. It's not so much, a few tenths here and there and we're right back in the mix."
Auer took eighth in the Saturday race, and is 31 points behind Ekstrom as the top non-Audi driver.