The first big technical controversy of Formula One's new engine era has its day in court on Monday with champions Red Bull confident they have a strong case in appealing Daniel Ricciardo's Australian Grand Prix exclusion.
Ricciardo finished second in his home race last month, his debut for Red Bull, but was disqualified hours later when stewards ruled his car had breached the new fuel flow regulations.
In what is seen as a critical test of the regulations accompanying the V6 turbo engines and energy recovery systems, Red Bull will say the fuel flow sensors cannot be trusted.
"We have got a very strong case," principal Christian Horner, whose team needs every point they can get after a troubled start to the season, said after last weekend's Bahrain Grand Prix.
"As more races have progressed, issues have become more evident - new evidence has come to light, or understanding has come to light - so hopefully we can present our case fairly and get the second place back that Daniel deserves."
Exactly what that evidence might be remains unclear, although Red Bull have experienced further problems with the fuel flow sensors since Melbourne and other teams - such as sister team Toro Rosso - have also found them unreliable.
The appeal hearing at the Paris headquarters of the International Automobile Federation (FIA) is due to announce the verdict as soon as possible and certainly before Sunday's Chinese Grand Prix.
McLaren will be among those following events closely, having benefited from Ricciardo's exclusion with Danish rookie Kevin Magnussen promoted to second and Jenson Button to third.
Red Bull are sure to argue that a technical directive relating to the issue, and sent out by the governing body before the start of the season to all teams, had no regulatory value.
"We are very confident that we can demonstrate that we complied with the rules at all times," Horner said after Melbourne.
"If you look at the facts, it's a very simple case. The rules are very clear. Technical directives are not rules. Did we break the rules or not? It's as simple as that.
"Technical directives are opinions, they are not regulations. And that's what the confusion is with this. I think people are not understanding that the rules within the technical regulations are explicitly clear. We did not break those."
The FIA has expressed confidence that the sensors it provides to all teams are accurate.
In Melbourne, instead of relying on the official sensor provided by the governing body Red Bull declared it too inconsistent and used their own measurements instead.
Ricciardo was then disqualified when stewards ruled his car had exceeded the maximum fuel flow limit of 100kg per hour - a breach which could have given a significant performance advantage over others.
The FIA says also that Red Bull ignored requests to reduce the fuel flow rate during the race.
Ricciardo, who had been the first Australian to appear on his home podium before his celebrations were cut short, said he had put the controversy to the back of his mind.
"Regarding getting the points back, I can't really think about it," he had told reporters last weekend before finishing fourth in Bahrain. "I have to drive as if I don't have them."