While the opening five races suggested that McLaren had benefited from its switch from Honda power to Renault, over the course of the remainder of the season the Woking outfit clearly struggled, and while it finished ahead of (Honda-powered) Toro Rosso, it was clear that the Japanese power unit hadn't been the root all the multi-championship winner's problems.
Though Honda has to take a huge step forward as it partners with Red Bull, a team not known for its patience, the Japanese manufacturer's F1 boss, Masashi Yamamoto, admits that the biggest difference between McLaren and Toro Rosso was the level of communication.
"The biggest change to Toro Rosso is we had much better communication with the team compared to the past," he tells Motorsport.com. "As a result, we had better connection between the chassis and power unit on the technical side.
"In terms of the engine itself we were able to see the improvement of reliability and performance," he continues. "We had Spec-2 and Spec-3 and improved the performance gradually. It was a good preparation for next year.
"We had some troubles at the beginning of the year," he admits, "reliability issues, and some delay on development but in the end both reliability and performance improved."
Asked if the significant improvement in 2018, compared to the previous three seasons, had surprised him, Yamamoto admits: "Not really a big surprise.
"The key point was the race performance in Canada," he continues, referring to the first significant upgrade of the year. "We were able to prove we could step forward to a certain level and were able to get trust from Red Bull. After that, we were able to continue in that environment.
"Red Bull was also seeing that. I think the relationship is quite stable and good, and we are getting that trust. I'm excited and looking forward to next year. If we can accomplish or complete our programme for next year on schedule, we can have a good relationship and results with Red Bull."