Red Bull needs to "worry" if it cannot supply a "competitive car" to Max Verstappen for 2021.
That is the implied warning in the latest rare comments made by the Dutch driver's father and co-manager Jos Verstappen.
"Max has a competitive engine in his contract, but that's also our premise," Marko told Auto Motor und Sport. "Without an engine with which we can win the world championship, the project is not interesting for us."
Jos Verstappen, however, is now making clear that the 23-year-old driver's camp is already not happy with Red Bull's pace.
That is despite the fact that Marko has been saying repeatedly that the world championship is even a possibility in 2020.
"Helmut can say whatever he wants, but I don't see it happening and I'm disappointed," Jos Verstappen told the Dutch publication Formule 1.
"Especially at the start I was very disappointed. Then I found out about the real situation. What can I say? We are too slow," Jos, a former F1 driver, added.
"We want to become champions, but that will not happen this year. Or at least not with the car as it is now. We have no chance.
"We have to accept that, but it's not what we want. It surprised me when the gap to Mercedes was so big.
"At Mercedes they win because of the people who make up the team," Verstappen snr insisted. "Therefore, Red Bull should organise the team better, discover where the problems are and work on them.
"Ultimately, it is the laptimes that count, and if you look at them, we fall short."
And so the spectre of Verstappen's potential departure from Red Bull is now looming, especially with Honda deciding to quit the team after 2021.
"We wait and see what happens," Jos told De Telegraaf. "We have little use for words to the outside world, but it is time for Red Bull to put down a car with which you can become a champion.
"If Max has a competitive car next year, they don't have to worry about anything," he added.
Speaking to Auto Motor und Sport, Dr Helmut Marko said: "Honda will build a new engine for 2021. That should make up for some of the shortcomings compared to Mercedes."