Red Bull were talking to Volkswagen about a Formula One partnership before a diesel emissions scandal seemingly scuppered plans, said boss Christian Horner.
Renault look like having no takers for their upgraded engine in U.S. Grand Prix after Red Bull's Daniel Ricciardo said it did not look enough of a step up.
Hamilton's hopes of clinching 3rd F1 world title at the U.S. Grand Prix were boosted when Vettel, said he would have a 10 place penalty on the starting grid