McLaren racing director Eric Boullier has admitted the reliability problems which have struck the team during testing have put "maximum" strain on their relationship with engine partner Honda.
The team were hit by yet another power unit problem on the first day of the second test, following four such failures the week previously. The latest issue forced Honda to change then engine in the back of Stoffel Vandoorne's car during the lunch break, which cost him an hour of running in the early-afternoon.
Speaking to reporters at lunch, Boullier admitted McLaren's relationship with the Japanese supplier is under pressure.
"Maximum [strain]," he said. "Obviously we are in Formula 1, we are racing and we have to perform, so the pressure is obviously huge.
"We put the maximum pressure on all of our relationships with Honda and it's the same from them. We can't put a foot wrong, we need to be able to deliver the best car as well, so this is both sides."
When asked if it could jeopardise their partnership, Boullier insisted the two companies have a solid contract which lasts for several years.
"No. We have a contract in place and actually normally it's seven years in every marriage or relationship, not three! We don't even think about it. There is a solid contract between us, a long-term contract and obviously we want to build on it."