Lewis Hamilton and Charles Leclerc have been disqualified from the United States Grand Prix after excessive skid-block wear meant their planks did not conform to F1's Technical Regulations.
Post-race checks carried out by the FIA's Technical Delegate discovered the infringements after the 56-lap event on a bumpy Circuit of the Americas.
Hamilton had closed into within 19 points of Red Bull's Sergio Perez in the Drivers' standings with second, having pushed Max Verstappen all the way to the end following a fascinating strategic battle.
Leclerc on the other hand had slipped from pole to sixth by the end of the race having been left on a one-stop strategy by Ferrari.
Following an investigation, the stewards' report for Hamilton read: "During the hearing the team acknowledged that the measurement performed by the FIA Technical Team was correct and stated that the high wear on the skid pads was probably a result of the unique combination of the bumpy track and the Sprint race schedule that minimized the time to set up and check the car before the race.
"The Stewards note that the onus is on the competitor to ensure that the car is in compliance with the regulations at all times during an event. In this particular case, the rear skid in the area defined in the Technical Delegate’s report was outside of the thresholds outlined in Article 3.5.9 e) of the FIA Formula One Technical Regulations, which includes a tolerance for wear.
"Therefore, the standard penalty for a breach of the Technical Regulations is imposed."
The same ruling applied for Leclerc, with both teams able to appeal the decision.
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The disqualifications mean Alex Albon moves up to ninth to secure two points for Williams but the spotlight will instead be shonen on teammate Logan Sargeant.
The American rookie has come under intense scrutiny in recent months following a number of incidents but having shown strong performance across the weekend, a shift up to 10th provides Sargeant with his first career point in F1.
It brings a welcome close to the event for the United States, who can celebrate a score for one of its own drivers for the first time since Michael Andretti for McLaren, 30 years ago.