Lawson filled in for the injured Daniel Ricciardo for five events, scoring his first points at the Singapore Grand Prix with what remains the best Sunday result for any AlphaTauri driver this season.
But with Ricciardo set to return for the United States Grand Prix in Austin, the New Zealander's brief stint with the team ended on a low note with a first-lap incident in the Qatar sprint and a low-key run to 17th - the last of those to finish the race - in Sunday's grand prix.
Lawson will be at the US GP in his usual reserve role but he will miss Mexico in order to compete in the Super Formula doubleheader finale at Suzuka. He lies second in the championship, eight points behind leader Ritomo Miyata.
Asked by Autosport about the importance of finishing his Japanese season as champion, Lawson said: “It's very important. Very, very important.
“Obviously, I think it can help make a huge impact on my career, especially with how this weekend's gone.
"I'll be in Austin. And I'll fly from there to Japan for our last race in Super Formula. So between now and then I'll just be preparing for that, and I'll obviously be doing stuff with Red Bull as well.”
Conceding his frustration at ending his stint with AlphaTauri on a disappointing note, Lawson added: "I think obviously you want to go out on a high,” he said. “So this is pretty tough to finish off on. I think it's just something we need to look into.
“The first couple of races went really good, we were building up, and then this week, I think we just struggled.”
He continued: "I think as I said the races up until this point were going pretty well, but this definitely doesn't help that. I think it's pretty disappointing, to finish my run of races like this.”
Lawson could take heart from some encouraging words from Christian Horner, who made it clear that the Kiwi will get another chance.
“I think he's done a great job jumping in with zero mileage in the car,” said the Red Bull boss. “And he's acquitted himself well as a grand prix driver.
“And I think he's caught all our attention in terms of the job that he's done. It certainly won't be his last race in F1. I'm sure that with what he's done in these five races he's demonstrated that he deserves an opportunity in the future.”
Additional Reporting by Matt Kew
