In light of the persistence of Honda's engine troubles, McLaren's Eric Boullier says the relationship between the two partners is "strained".
Stoffel Vandoorne was hit with an electrical issue this morning which required a full engine change - the third in a week.
The reliability troubles currently offer a bleak prospect for McLaren-Honda, jst over two before the season gets underway in Australia.
"Obviously we are in F1, we are racing, and we have to perform," Boullier said.
"So the pressure is obviously huge and obviously we put the maximum pressure on all of our relationship with Honda, and the same for them.
"We cannot put a footstep wrong. We need to be able to deliver the best car as well, so this is both sides."
Boullier explained however that a common issue was at the basis of two of Honda's issues, providing hope a resolution is in the works.
"From the outside world it may look like it is a different problem, but at least two of the problems were the same," explained Boullier.
"So it can be addressed in time. The one thing is we are running the same spec as last week so obviously that doesn't mean there are any changes in this block or any modifications done.
"I think, the next spec will have addressed part of this problem, or most of this problem."
While the issues have hindered McLaren's development progress since pre-season testing got underway, the Woking outfit's racing director is not overwhelmed with worries.
"Obviously we would like more laps because we would like to test more parts, but the few we have done is good, and the correlation is good, so we can now build a bit on predictions I would say.
"For the rest, obviously I leave this in the hands of Honda to make sure that they investigate properly, they address it properly and we have to rely on our partner and we believe that they will do it."