Dr Helmut Marko has warned Pierre Gasly to drive more cautiously.
Marko is the top Red Bull official under team owner Dietrich Mateschitz, and he is targeting "a minimum of five wins" in the first Honda-powered year.
"I believe we also have a certain chance of the world championship," he told APA news agency.
Marko says dropping Renault and switching to works Honda power was "the best" decision Red Bull could have made.
Another decision was to replace the Renault-bound Daniel Ricciardo with Toro Rosso driver Pierre Gasly for 2019.
However, the Frenchman's inexperience showed in Barcelona testing, with two crashes.
"In the second crash we ran out of spares, so Max Verstappen could hardly drive on the last day," said Marko.
Nonetheless, he says Red Bull will treat Gasly and Verstappen fairly in 2019.
"Nothing will change in that way, but what we've seen in the tests is that Gasly is not yet on Verstappen's level. But we didn't expect that either," said Marko.
When asked about Gasly's testing form, Marko added: "Apart from the two crashes it was perfect.
"Especially the second crash hurt us. He should not allow himself to do that anymore," the Austrian added.
Finally, Marko was asked about the 'Brexit' story, and particularly Toto Wolff's claim that it could be a major issue for the UK-based teams this year.
"Nothing is eaten as hot as it is cooked," Marko said. "The country has to keep going.
"There may be one or two inconveniences, or something will be delayed, but that's not so important."
