Helmut Marko has reiterated his theory that Red Bull contributed to Lewis Hamilton's engine failure in Malaysia.
Mercedes team chairman Niki Lauda hit back at Marko's "nonsense", but fellow Austrian Marko thinks his theory is sound.
"It's strange," he told Germany's Auto Bild.
"Why do Mercedes suddenly no longer drive in quali-mode? Why are the new engines not being given to the customer teams as was planned?
"I think our theory seems to be right.
"As long as Mercedes does not know exactly what happens, the most obvious explanation is that it is because they are now going at full power."
Ricciardo and Verstappen finished first and second respectively in Malaysia.