Ferrari suffered a nightmare double retirement at the Azerbaijan Grand Prix to hand another huge opportunity to Max Verstappen and Red Bull.
Ferrari had claimed pole position through Charles Leclerc on Saturday, with Carlos Sainz starting fourth, but within just 20 laps of Sunday's race both its cars were out of the race.
Sainz retired from fourth position on Lap 9 with what the team later confirmed to be a hydraulic issue.
Leclerc had been beaten to Turn 1 by Red Bull's Sergio Perez but was on a different strategy to both Perez and Verstappen thanks to a well-timed stop under a Virtual Safety Car.
Any chance of a spectacular fightback for Leclerc was thwarted on Lap 20 when smoke poured from the back of his Ferrari.
Leclerc immediately returned to the pits and retired the car, with what Ferrari confirmed was a power unit issue.
"It hurts," Leclerc told Sky Sports shortly after his race ended. "We need to look into it so it doesn't happen again. I don't find the right words to describe. It's really disappointing. We need to look into it."
Asked if it was a significant blow in the championship, he added: "It's more than significant. Yeah, I don't really have the words to be honest, I came straight from the car to here.
"It's just a huge disappointment and I just hope we can jump back from it and be on top of those things."
Sainz added: "We were looking forward to start pushing after 9 laps of managing the tyres and trying to have a good introduction to the tyres and suddenly the hydraulics went and that was it, even more frustrating to see Charles not finishing and have another issue, for sure a tough day for all of us.
"We are a team, we will go through different moments in the year, this one is one of the most difficult and frustrating but we will try and make sure we recover it."
Ferrari also saw two customer cars suffer failures, with Alfa Romeo's Guanyu Zhou and Haas' Kevin Magnussen both retiring midway through the race.
The team will only have seven days to get on top of its issues before racing again at the Canadian Grand Prix in Montreal.
Leclerc was already nine points down on Verstappen in the championship. Verstappen was leading the race and had the fastest lap when Leclerc's race ended, meaning the reigning world champion could extend that lead to 35 points by the end of the race.
If Perez finishes second, he will also leap past Leclerc in the championship standings.
Leclerc's once-promising season has fallen apart in recent races. At the Monaco Grand Prix, his home race, a Ferrari strategy turned a likely victory into a fourth place finish.
Despite claiming six pole positions from eight races this year, Leclerc has only converted two of them into victory -- his last this season was at the Australian Grand Prix on April 10.
Reliability issues had been a Red Bull problem at the start of the season. Verstappen's car failed to finish two of the first three races and after the Melbourne race the Dutchman was 47 points behind Leclerc.