Red Bull fears the impact suffered by Sergio Perez during the first corner melee at the Hungarian Grand Prix has permanently damaged the Mexican's Honda power unit.
As the field barreled down to the first corner at the start in the wet conditions, an out-of-control Valtteri Bottas rammed the rear of Lando Norris' McLaren and then side-swiped Perez.
The Red Bull driver was able to collect himself and rejoin the track only for his engine to shut down a little further down the road.
Meanwhile teammate Max Verstappen who was hit by Norris as a result of Bottas' nudge was able to take the race's second start but damage to the Dutchman's RB16B meant that he was only able to finish P9, a result that allowed Lewis Hamilton and Mercedes to recapture the lead in their respective championships.
"That’s the brutality of racing, isn’t it?" said Red Bull team boss Christian Horner after the race.
"I think that unfortunately you saw Valtteri make a poor start, he obviously misjudged his braking and he’s done a great job for Mercedes in taking out both of our cars."
Horner feared that in the carnage, Perez's power unit had suffered irreparable damage.
"It lost all its water immediately," said the Briton. "We'll have to look into it in more detail, but the initial reports are it will no longer be in service."
Perez will therefore likely move on to a third and final unit at the Belgian Grand Prix at Spa, which would spare the Mexican a grid penalty but would put him on the fringes of a grid drop later in the season.
In Hungary, after Saturday's running, Verstappen was also allocated a third engine after Honda diagnosed an issue on the unit that had survived the Dutchman's crash at Silverstone.
For Horner, adding a fourth unit to either driver's pool of hardware later in the season is almost a certainty.
"And that's hugely frustrating for Honda because it's not due to reliability," he said. "It's because of accidents that we haven't caused. So they're feeling the brunt of this as well as we are on the chassis side."
Despite the adverse circumstances of late, Horner insisted Red Bull will return to the fray after the summer determined to fight.
"We’re within the difference of a first and second place in points difference as we go into the summer break," he said.
"We’ve had some hugely bad luck the last couple of races. It’s been been pretty brutal in damage and parts and engines.
"But we’ll push ourselves down and we will come out fighting for the second half of this championship because obviously it’s been a tough couple of weeks.
"But things can turn around very quickly, as you’ve just seen. And there’s a long way to go in the championship."
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