Cape Town - Max Verstappen feels Red Bull have been "two races behind" Ferrari and Mercedes in terms of engine updates throughout this season given that Renault have delayed giving them new parts.
As a customer of Renault, it is usually the French manufacturer's works team that gets the upgrades as soon as they are available while Red Bull have had to wait for more parts to be made.
But while Verstappen understands that, he says it has left Red Bull "two races behind" their main rivals.
"If there are new parts, they will of course go to the factory team first, which is also logical but it's a pity for us," he said.
"You just know that at Ferrari and Mercedes these are immediately introduced and then they might have advantage of that for one or two races, before the rest takes a step.
"So, we are always two races behind."
Verstappen's complaints are just the latest in a long list of complaints that Red Bull have had about engine partner, Renault.
This acrimony led to the Milton Keynes team announcing that they will swap to Honda power from next season.
That, though, comes with a few issues of its own in the latter part of this championship.
Verstappen added: "Especially now they have their own factory team, you're always a little behind on things.
"Now that it's certain that you are making the switch to Honda, that will not work in your favour, let's put it like that.
"But that's how these things work, and we know that, so you just need to accept it."
He is, however, hoping that upgrades to the RB14 can off-set any engine deficit.
"I hope we will continue to develop the car well.
"The engine is a difficult story. "We are better than them [Mercedes and Ferrari] in terms of car, so car-wise they are the ones who need to catch up."