MONZA, Italy - Engine supplier Renault apologised to Formula 1 champion Red Bull at the 2012 Italian GP on Sunday after the team failed to score a point in a race for the first time since 2010.Double World champion Sebastian Vettel rolled to a halt with what was diagnosed as alternator failure - the same problem that denied the German a victory in Valencia in June when he started on pole.DREW A BLANKAustralian Mark Webber retired after inflicting too much damage on his tyres to continue safely. The last time Red Bull drew such a blank was in South Korea in October 2010.Renault engineer Cyril Dumont said: "We changed the alternator on Sebastian's car on Saturday but unfortunately we had the same failure in today's race."We are still looking into why this happened but we do know that even though the alternator was being operated entirely within the prescribed range the part itself overheated and shut off the power supply."We have to apologise to Red Bull Racing as clearly this has hurt us in the championship. We have no option but to sort it out and it will still be a priority before Singapore."SAVE THE ENGINEVettel, now fourth in the championship and 39 points off the lead after starting the day second, said he knew he had a problem about 300m before the car stopped when his pit crew told him to pull over immediately to save the engine.He had by then already collected a drive-through penalty for forcing Ferrari's championship leader Alonso on to the grass and gravel at 330km/h.Team principal Christian Horner said the two failures would be extremely costly, even if Red Bull still leads the Constructors' standings by 29 points from McLaren, with seven races remaining.Horner told reporters: "Very disappointing but we need to work with Renault to try to understand it and make sure it doesn't happen again."Sebastian did nothing wrong. He drove as hard as he could and this circuit unfortunately exposes our weakness."