Masashi Yamamoto says the failed McLaren collaboration was Honda's "biggest lesson" since the Japanese marque returned to Formula 1.

In Monaco, the Honda-powered Red Bull of Max Verstappen diced for the race lead with winner Lewis Hamilton. He didn't even finish on the podium, but Yamamoto says it is one of the important "small victories".

"We have learned that the most important thing is to celebrate the small victories as steps forward," Yamamoto, Honda's F1 boss, told Speed Week.

It has been a hard journey for Honda since returning with McLaren in 2015, but Yamamoto says the carmaker is now targeting actual race wins.

"We must continue to focus on race wins, that's the biggest goal," he said.

But the biggest lesson, he added, was the utter failure of the McLaren days.

"That we were not fully prepared was the biggest lesson," said the Japanese.

"If we could start again, we would definitely be better prepared to get into a better position more quickly."

Honda and McLaren split after 2017, but from 2018 Honda teamed up and started making clear progress with Toro Rosso. This year, Honda started working with Toro Rosso's parent team, Red Bull Racing.

"What we went through with McLaren was precious lessons, and we learned a lot from it. That has brought us to where we are today."

Now, Honda is setting its sights on Mercedes.

"It will be tough, but if we stay on the road one day we will be able to fight them. We are working in that direction.

"Motor sport is all about winning and losing, although it is probably 50 per cent pressure and 50 per cent fun. We need to make progress according to our plan.

"Formula 1 is the best stage to tackle this challenge," added Yamamoto.