Although Max Verstappen has called for more power from Honda in 2020, the Japanese manufacturer has warned that significant improvements are unlikely to be found next year.
Red Bull's first season with Honda resulted in three wins for Verstappen, who also secured the first two pole positions of his career.
Despite the results, neither Verstappen or Red Bull could fight their way into title contention, as Lewis Hamilton and Mercedes' stunning start to 2019 effectively ended the race by mid-season.
As has become something of a tradition, Red Bull's development through the season – aided by Honda doing likewise – helped the team end the season strongly, with Verstappen taking a dominant Brazilian GP win sandwiched by podiums in the United States and Abu Dhabi.
But Honda has suggested that starting 2020 in a similar vein will be crucial, with engine output beginning to plateau.
"We could show our improvement, our good positive progress this year, not only with Red Bull but also Toro Rosso," Honda Formula 1 technical director Toyoharu Tanabe told Racer.
"It was very nice for all the people working for this project and people in Honda. So I want to keep this momentum for next year.
"The development for next year has already started. And then we need to push more to achieve our goal.
"I think it's harder than previous years. We need to be precise in every single area, in terms of hardware, also software and then trackside management as well. So, we keep pushing.
"The PU means the ICE, MGU-H and K, and all the systems, water and oil. Also tools, software, we have a lot of things to do. But a big step? Maybe that's getting difficult."