Red Bull advisor Helmut Marko has slammed engine partner Renault after a difficult start to the 2015 season in Australia.
Daniel Ricciardo could not run at all in Friday's second practice session due to an engine problem, and in the morning the Australian had been just tenth fastest.
The power unit is believed to be fixeable and Ricciardo will be able to use it again, but Marko indicated that the relationship with Renault remains fragile.
"The engine is broken after 50 kilometres," Marko told the Austrian broadcaster ORF.
"We have a meeting on Wednesday in England. Those in charge of Renault are not yet here, they're coming tonight, but it cannot be like this.
"We are promised again and again 'Next time it will be better, the test results are encouraging'.
"But if you have an engine failure after 50 kilometres, that is incomprehensible.
"We wanted an improvement and we have taken a step back. The gap to the top now is frightening."