Honda F1 Motorsport boss Yasuhisa Arai has admitted the challenges of returning to Formula 1 have been much harder than the company had envisaged, but remains confident its approach will eventually yield the results anticipated.

The Japanese firm made a high-profile return to F1 this season in collaboration with McLaren, reviving an iconic partnership that dominated the sport in the late 80's and early 90's.

However, Honda has struggled to get a successful grasp on the latest regulations, with its power unit both down on power and troubled by persistent reliability problems that have hampered McLaren drivers Fernando Alonso and Jenson Button throughout the 2015 season.

Indeed, though Honda and McLaren have always maintained the party line that they expected a difficult start initially as it brought itself up to speed with its rivals, Arai accepts that the issues and lack of competitiveness have been more acute than it could have anticipated.

"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.

"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."

Indeed, after suggestions of discord from the McLaren side and pressure from Honda to turn the project around, though Arai doesn't explicitly say his job is under threat, he remains certain he is the man to succeed.

"I think Honda's development method is very different to Formula One and McLaren," he continued. "Of course I have big pressure on my shoulders - especially from the fans, the Honda board and my colleagues, but this is completely normal.

"I think that I have what it takes to drive this project, but I can't decide my own future, neither can the media or McLaren board members. I hope to continue driving this project and I believe that our board members trust me emphatically.

"Every step of this new project has been discussed with McLaren management. Every day we are in discussion. I know that they are under pressure from sponsors, but we trust and help each other to come up with good, innovative ideas.

"Working with the two different cultures within the team has made us stronger and more creative. It's a very good relationship and a very good team. I trust everyone in the team, and we wouldn't be McLaren-Honda without each and every one of them. We wouldn't be fighting as hard as we are without their support and hard work."