In last weekend's Motegi season finale, Honda scored a first pole position and a second win with the updated Type S version of the NSX-GT as Team Kunimitsu pair Naoki Yamamoto and Tadasuke Makino dominated.
But it wasn't enough to stop Nissan from ending a losing streak going back to 2015, as Honda's best-placed car in the points pre-race, the Real Racing car of Nobuharu Matsushita and Koudai Tsukakoshi, could only manage fifth.
Nissan had looked like favourites to take the title after scoring victory at Sugo on a day that heavily favoured the Michelin tyres of the two NISMO-run cars that finished first and second, while the Impul Z that ultimately won the title finished fifth despite carrying a stage three fuel flow restrictor.
Both the Kunimitsu and Real NSX-GTs had looked good for a strong result in the dry, but the rain meant they ended up eighth and 12th respectively.
Honda's head of car development Tomohiro Onishi feels this was the race in retrospect where the Sakura marque lost out to Nissan.
"When I saw this year's schedule, I realised that the first half of the season would be tough, but even then in most races we were able to score good points and things were looking promising," said Onishi.
"The point at which the momentum shifted was the wet race at Sugo. There we had to score big points at a track well suited to our car, and we couldn't. I think that was the biggest cause for our defeat."
Real Honda falls short again
Despite a promising start to the race for the Real Honda, as Matsushita went from 10th on the grid to fourth early on, the car shared by he and Tsukakoshi lacked the pace later in the race to mount a real challenge.
Finishing fifth also cost the team third in the standings - and status of top Honda crew - to Team Kunimitsu.
"I was quite aggressive to pass some cars [after the start], then I had a chance to fight with Baguette," Matsushita told Motorsport.com. "I was able to get ahead of him once, but it was not enough [to keep the position].
"Then things calmed down and I handed over to Koudai, but after that the pace with the tyres wasn’t good, and we struggled a lot. That was it, I think. We didn’t have the pace to catch up. It’s quite a big shame, but that’s how it is.
"I enjoyed the race a lot actually, going from P10 to P4 [in my stint]. But finishing fourth in the standings… it's nothing!"
The chief engineer of the #17 Real Honda, Yasuhiro Tasaka, admitted that the team was baffled that using the same set-up that had worked well in the previous month's tyre test at Motegi in similar weather conditions didn't work.
"When we started running, we realised that the grip was worse than at the time of the test, even though the car [set-up] was the same, and the weather was almost the same," Tasuka told Motorsport.com's Japanese edition.
"We were planning to try some major set-up changes, but we were just thinking, 'why is it like this?'
"During the test we were able to evaluate the tyres properly, and we arrived with the same set-up we used that time. But looking back, the tyre temperatures were a little low, so I think we weren't able to warm them up enough."
