Max Verstappen and his father Jos have questioned their commitment to Red Bull.
At Spa, in front of thousands of Dutch fans, the 19-year-old's car broke down for the sixth time in 12 races so far this year, with engine supplier Renault getting the blame.
"All we can do is put pressure on our supplier and say 'Get your act together'," said team boss Christian Horner.
"We pay a lot of money for this engine and we're not getting value."
Amid rumours that he wants out of his contract before it ends in 2019, however, Verstappen pointed the finger at Red Bull.
"This doesn't happen in a top team," De Telegraaf quotes him as saying.
"At the start you can call it luck but it's no longer that.
"I don't know what the alternative is, but continuing like this makes no sense.
"Christian Horner can keep saying that setbacks make me stronger, but winning races would also make me stronger."
Verstappen's father Jos also indicated that their patience with Red Bull is up.
"This cannot go on. It's unacceptable," he is quoted as saying by Algemeen Dagblad newspaper.
"What it means for the future? I'm not saying anything about it now. We will have to calm down and sit down together, but it cannot continue in this way."
The championship continues next weekend with the Italian Grand Prix.
