Christian Horner has revealed the seriousness of the technical issues that threatened to derail Max Verstappen's Hungarian Grand Prix weekend.
The Red Bull driver took a fresh power unit ahead of the race, after being hampered by power loss issues during qualifying.
The issue meant Verstappen started the Grand Prix from 10th place but, because he still had power units to use in his allocation, he didn't take any grid penalties.
Verstappen went on to take a remarkable victory from the fifth row of the grid to extend his championship lead over Charles Leclerc to 80 points.
Red Bull boss Horner revealed after the race that identifying the issue after qualifying prevented a retirement.
"We changed the power unit because a part broke on Saturday for Max," Horner confirmed to media, including RacingNews365.com.
"In hindsight we are very happy that the part broke on Saturday, because otherwise the engine would have broken 12 kilometres later on the way to the grid.
"We replaced the entire power unit instead of trying to repair it. We also replaced the power unit on Checo's [Sergio Perez's] car as a precaution."
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Horner confirms mid-race clutch issues for Verstappen
Equipped with a fresh power unit, Verstappen battled towards the front of the pack to pass title rival Charles Leclerc for the lead.
However, Verstappen was forced to repeat the overtaking move after a spin at the exit of Turn 13, which briefly put him back behind Leclerc.
Verstappen commented after the race that he believed the spin was related to a clutch issue, a problem which was also confirmed by Horner.
"We had an issue with the clutch on Max's car, which he was able to manage," added Horner.
"The temperatures were getting a bit too high. That was also why we left him a gap to Carlos after the first stop.
"But when we released him, after the clutch problem was under control, he had great speed."
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