Dr Helmut Marko has dismissed Renault engineer Remi Taffin's recent claim that Red Bull's engine supplier Honda is "one step behind" all of the other engine manufacturers in F1.
"I don't know what part of the season he was thinking about," Marko, a top official at Red Bull, told Germany's Motorsport-Magazin.com.
After a prolonged period of tension between Red Bull and its long-term customer supplier Renault, they split at the end of 2018.
Marko continued: "At the end of 2019, Honda and us were at Mercedes' level, and even ahead of them on tracks where engine power is important like Mexico and Brazil.
"If we look at mechanical problems, you can conclude that our engine is more reliable than Renault's. So we are not upset that we are no longer with them," he added.
"And if you look at the constructors' championship, Renault was only in fifth place, and I don't know how many points they lost to us."