Italian GP: Red Bull says it cannot afford any more retirements after Sebastian Vettel's Monza disaster

Vettel retired from the Monza race with an alternator failure on lap 48 - the second time his car had been stopped this weekend with the issue following a similar problem in third practice.

Horner was clearly deeply disappointed by the situation, which comes after the team lost a likely victory in Valencia with the same problem. He urged Renault to address the matter with some urgency.

"I think the most important thing is that we need to find rectifications for the faults that have occurred," explained Horner.

"DNFs are extremely expensive and it is our first non points scoring race since [Korea] 2010 - which also happened to be an engine failure that cost us on that day as well. We cannot afford to not be finishing races."

Horner was unaware of the cause of the alternator failure - which Renault believes was caused by overheating - but thinks it vital his outfit works with the French car manufacturer to get on top of the matter.

"We have had two race-stopping failures: one that cost us a certain victory and today one that cost us a sensible amount of points. It is extremely costly and something that needs to be rectified for the remaining eight races.

"I think there was another issue on another car with the same component during the weekend, so it is very disappointing. But we need to work with Renault to understand it and make sure it doesn't happen again."

The other alternator issue hit Jerome d'Ambrosio in the Lotus on Saturday, when the alternator did not fail but was changed as a precautionary measure after qualifying.