The Mercedes driver had gone into the Suzuka race hopeful that the team could build on some promising potential shown in practice with a new set-up direction for the W15.
But he was put on the back foot almost immediately from the restart of the red-flagged race after a minor clash with Leclerc in the opening sequence of corners left him with car damage.
That meant he suffered from excessive understeer, and explained why he was so happy to move over for team-mate George Russell, who had closed on him in the first stint, a few laps later.
Speaking to F1 about whether the car had not delivered what he'd hoped for in the race, Hamilton said: “I mean, the car is never what I would [have] hoped it would be. It's never what we'd hoped it would be.
“I got some damage in the first stint in the restart with Charles, and I had massive understeer, like huge, huge understeer. So that's why I decided to let George by, because he seemed quicker.
“I just couldn't turn the car, and it took us two stints to finally dial more and more wing in to make up for that loss. Last stint I was better, but it was too late. I had 10 seconds to regain.”
While Hamilton had been hugely encouraged by a new-found confidence in the W15 that Mercedes’ fresh set-up direction had given it, he was clear he was not leaving Japan feeling too upbeat.
“I don't know if you can take many positives from the weekend,” he said.
“I mean the car has finished, which is good. But we're like you know seventh, eighth, ninth fastest…”
Mercedes trackside engineering director Andrew Shovlin said the squad’s weekend had effectively been wrecked by its poor qualifying performance, where neither driver had been able to extract as much from their car as they would have liked.
“We weren't quick enough in qualifying so were starting too far back to challenge for the podium,” he explained. “Early in the race, our pace was simply not good enough, too.
“We'd decided to go to the hard tyre at the red flag as we felt there wasn't much threat from behind, and it was our best way to offset and try something different.
“Towards the end of that stint we were really struggling with low grip. We couldn't stop early as there was too much traffic in the window, so we stayed out until we had cleared it.
“Unfortunately, by then, we had lost a chunk of time. The second and third stints were more encouraging, but we'd lost too much time by that point to get back into the mix.
“We know that we are not quick enough at the moment, so we will continue [to] work hard to improve that.
“Despite the challenging result, it has been a useful weekend to learn more about our car and develop our understanding of the W15.”
Watch: F1 2024 Japanese Grand Prix Review – Normal Service Resumed
