Honda's return to F1 as McLaren's engine partner has not gone according to plan with the Japanese company admitting they "didn't imagine that it would be this hard".
There were hints of nostalgia up and down the paddock when McLaren confirmed Honda as their power unit supplier from the 2015 season onwards with many hoping it would lead to a return to the glory days.
Of course there is still plenty of time to rekindle the success the two parties enjoyed during the late 80s and early 90s when Ayrton Senna and Alain Prost won four titles between them.
But Honda is the first to concede that things have not gone according to plan so far this season with Fernando Alonso and Jenson Button not only struggling at the back of the grid, but also troubled by reliability woes.
Honda motorsport chief Yasuhisa Arai admits they have underestimated just how much the sport has changed.
"Expectations were always going to be high because of our illustrious history with McLaren," he said. "Most of the fans have a great image of McLaren-Honda's heritage so they expected us to return to Formula One and be competitive immediately. Obviously this has not been the case.
"The sport has changed immensely since the McLaren-Honda 'glory days'. The current technology is much more sophisticated and it is tough to make a good racing car. We knew it wouldn't be easy, but perhaps we didn't imagine that it would be this hard.
"We believe that our compact power unit layout will prove to be very competitive; however we knew from the start that it would cause problems with heat rejection. We now know which area is affected, and in the second half of the season we will apply new parts to resolve the issue and apply more horsepower to improve our competitiveness.
"I certainly didn't imagine technology wise what we would be facing, but I have complete confidence in the direction we have taken with our power unit. We needed to create something radical in order to beat the top teams, and that is our ultimate goal – to beat the best."
Formula 1 rules are pretty complex and the testing restrictions have not helped Honda's cause with Arai explaining the "domino effect" their problems with the MGU-H has had, preventing them from making progress at a much a faster rate.
"The current regulations of the whole power unit package are very complicated so one small component triggers a domino effect of other items leading to the issues that we have been seeing," he said.
"Let me put this concept of the domino effect into a technical example: if you try to harvest energy using the MGU-H, it puts a strenuous workload on the turbo. When the turbo is under stress, it cannot do what it is supposed to do, which is to force more air into the engine, thus leading to decreased power output. This is the result of one component working against the others, instead of working together.
"These types of technical chain reactions which lead to vehicle stoppage were definitely more than we calculated, or more than we envisioned. The difficulty with this is that you cannot calculate precisely without running the car in actual conditions, on track."