Leclerc took his fourth pole position in a row in Sochi, but Vettel was ahead on lap one after making the most of a slipstream into Turn 2 that his team-mate did not make an attempt to break in an arranged plan.
However, Vettel was not so compliant with his end of the deal, refusing to let Leclerc through to take the lead again, before Ferrari took matters into their own hands to swap them at the pit-stops – only for the race to then unravel as Vettel suffered MGU-K failure and Mercedes took a one-two.
Asked if Leclerc's form had influenced his decision on-track, Vettel said: "No, not at all.
"Obviously I'm not happy if I am slower, whether it's practice, qualifying or race but that has been the same, not just this year but years before as well.
"There are certain things this year I've struggled with here and there with the car which didn't allow me to extract my best, I don't think it would have been any different if anyone else was in the car.
"Charles is doing a very good job, but I think it's largely - and I genuinely believe it's first a race against yourself and then the others.
"There have been races where things didn't fall into place and therefore things didn't look great on the outside. But I think we were tackling the right things on the inside. So I'm not worried."
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