Niki Lauda has all but written Sebastian Vettel out of the title race after he suffered a second alternator failure at Monza.
The reigning World Champion previously lost a chunk of points - one could argue 25 - when his Renault engine's alternator expired in Valencia.
It was a similar story - although not involving as many points - at Monza, dropping Vettel to fourth in the Drivers' Championship where he trails Fernando Alonso by 39 points.
"These quality problems could cost Vettel the title," Lauda told the Osterreich newspaper.
"An error can occur but it needs to be fixed immediately and must not occur again.
"Theoretically the Championship is not yet lost for Vettel but in practice it is."
As for who will win the title, the 63-year-old Austrian believes "Alonso is clearly on course for the title as Ferrari are very reliable."