Engine performance is the key to Daniel Ricciardo’s next contract.
That is the claim of the Australian driver’s boss Christian Horner, who reiterated in Baku that Red Bull wants to keep him.
But Mercedes and Ferrari are reportedly also interested, and Horner admitted that the hierarchy of engine performance in F1 is a key to the eventual outcome.
Red Bull is highly competitive once again in Baku, but Horner told Auto Bild: "Even the Williams is better than us on the two kilometre straight."
The team is openly considering whether to stay with Renault next year or switch to Honda power.
"Renault is working hard, but our relationship is a bit of a roller coaster of emotions," Horner said.
He admitted Red Bull has a "great deal of interest" in how the Toro Rosso-Honda collaboration develops, "because for the first time in 10 years we have an option".
And that is a key to the talks with Ricciardo.
"We will talk behind closed doors," Horner said. "But it’s no secret that our preference is to keep Daniel.
"His only question mark is engine performance."