Red Bull duo Max Verstappen and Sergio Perez were just eight seconds away from having to start from the pitlane for Sunday's Spanish Grand Prix.
Verstappen and Perez went on to score Red Bull's second one-two of the season, a result that has elevated the Dutchman into the lead of the drivers' standings and Red Bull to the top of the constructors' championship.
The pair were aided by the retirement of Ferrari's Charles Leclerc from a comfortable lead of the race in sweltering conditions at Barcelona's Circuit de Catalunya due to a power unit issue on lap 27.
Verstappen and Perez, however, came close to not making it onto the grid due to the same problem that affected Aston Martin drivers Sebastian Vettel and Lance Stroll just before the Miami Grand Prix.
Fuel is required to be 10 degrees below ambient [outside air] temperature two hours before the start of a race.
In the searing heat in Barcelona, the temperature at that stage was 35 degrees Celsius, requiring the fuel to be 25 degrees.
According to Auto Motor und Sport, it was not until the dying moments, and with the fuel in the cars at the correct temperature, that the Red Bulls were able to roll out of the garage just before the pit lane closed.
If the required temperature had not been met, then Verstappen and Perez would have been forced to have started from the pit lane, as Vettel and Stroll did in Miami.
Ferrari team principal Mattia Binotto has suspicions Red Bull had issues in ensuring its fuel was legal before taking to the grid.
“I can imagine it was down to the fuel temperature,” said Binotto. “In the tank, they need to be a maximum 10 degrees below the ambient.
"Per regulations, it should be at all times [that temperature] during the event. So not only when the car is going out but as well in the garage itself.
"So I don't think a fire up, trying to heat up a fuel tank would be sufficient because the fuel should be at all times not more than 10 degrees [below ambient].
“So I can only trust the FIA. It’s difficult to understand that they were maybe heating up the fuel through a fire-up because it would not explain… as I said, it should be at all times.
“I can only trust the FIA and I’m pretty sure they are comfortable. They checked.”