Max Verstappen was forced to abandon his final lap in Singapore Grand Prix Formula 1 qualifying due to a lack of fuel, his Red Bull team have revealed.
F1 rules require a one litre sample for FIA testing post-session, with disqualification the penalty if it can't be obtained - something Lewis Hamilton and Sebastian Vettel have suffered in the past.
Despite being on course for a pole lap at Marina Bay, he was ordered to box by race engineer Gianpiero Lambiase in Sector 3 - unleashing a torrent of swear words over the radio.
He was left in eighth place with Charles Leclerc grabbing a ninth pole of the season for Ferrari.
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Owing to the conditions, Red Bull had fuelled Verstappen for five laps, but the lap he aborted was his sixth of the session.
Team boss Christian Horner admitted they had no choice but to bring him in.
"I think it was a miscalculation on our side," he told Viaplay.
"We fuelled the car for five laps and because the track was ramping up so quick, we got an extra lap so he was perfectly placed.
"But, obviously it's critical to give the fuel sample so it's the hardest call in the world when he's two-and-a-half seconds up on his lap time.
"If you don't give the sample you're starting from the pit lane, so it is frustrating but great pace in the car and phenomenal performance by Checo [Perez in second]
"I mean, just to miss out by two hundredths was really tight.
"We made it harder for ourselves qualifying eighth [with Verstappen] but we'll give it everything, and these cars can actually race.
"It will be important for Checo to get a good start tomorrow as well as it is a long race."