BOSTON — Klay Thompson might as well have spent Game 2 of the N.B.A. finals on Sunday launching the ball straight into swirling winds. His field-goal attempts veered left and right, fell short and carried long.

Afterward, knowing Golden State would need him to be more productive as its series with the Celtics continued, Thompson sought to remind himself that he was good at basketball. So he fired up a laptop and watched old clips of a familiar figure: himself.

“I remember being in college,” he said, “and when you’d go through a shooting slump, the video guys would pull up a great game when everything seemed in unison, and your body was working so well that the ball was just flowing off your fingertips.”

All Thompson needed to do, he said, was search for “Game 6 Klay” on YouTube, and various high-profile reminders of his long-range acumen were readily available to him. Most recently, he scored 30 points and made 8 of 14 3-point attempts in Golden State’s Game 6 win over the Memphis Grizzlies last month to close out their Western Conference semifinal series. He also famously scored 41 points, in a performance that included making 11 of his 18 3-pointers, in 2016 in Game 6 of the Western Conference finals against the Oklahoma City Thunder.

“There were some very high-pressurized situations I was in, and I ended up shooting the ball well,” he said. “When you can do it when your back is against the wall, you can do it at any given moment. It’s just about keeping that mental strong.”

If nothing else, Thompson is familiar with keeping, as he put it, that mental strong. His celebrated comeback after missing two full seasons because of injuries has culminated in another trip to the finals, his sixth with Golden State. But he was clearly disappointed with his effort in Game 2 against Boston, as he shot 4 of 19 from the field and finished with 11 points. On the bright side, he said, the Warriors drubbed the Celtics to tie the series ahead of Game 3 on Wednesday night in Boston.

“It feels good going 4 for 19 and winning by 20,” said Thompson, referring to Golden State’s 107-88 win. “I’d rather do that than go 13 for 19 and lose by 10. Been there, and that’s never fun.”

On Tuesday, Thompson arrived for his news conference wearing one sneaker while he worked to fit the other with an insole. He was, in his own way, a work in progress, and that has been the case since January, when he was finally back in uniform after a 941-day absence. In 32 regular-season games, he shot a career-low 38.5 percent from 3-point range, but he offered flashes of his familiar greatness, and his mere presence on the perimeter helped create more space for teammates like Stephen Curry.

It has been more of the same for Thompson in the playoffs: some good, some great, some bad. His inconsistency should not be surprising given how long he was gone. His left knee and his right Achilles’ tendon are surgically repaired, so there were always going to be ups and downs as he sought to regain his rhythm and his conditioning. His teammates do not seem concerned.

“If you saw him now, you’d think he’s averaging 50 in this series,” Curry said. “He’s got a very confident look about him. That’s the best thing about him. It’s all about the work you put in. It’s about the mind-set.”

On Sunday, Thompson had a bit of a different look. He missed 9 of his first 10 field-goal attempts before he made a 3-pointer early in the third quarter that put Golden State ahead, 59-52. He pumped his fists, but was soon muttering to himself and shaking his head.

“When I watched the film, I probably seemed a little rushed,” he said. “I wasn’t underneath my shot.”

Even as the score grew more lopsided, Golden State Coach Steve Kerr left Thompson in the game against Boston’s reserves. But rather than unearth some confidence, Thompson missed his final four shots.

“I think he’s just pressing a little bit,” Kerr said. “He just wants so badly to do well that he’s taking some bad ones. I’m not particularly concerned about it because this isn’t the first time it’s happened. Klay has a way of responding to mini-slumps or whatever you want to call them.”

Thompson thought back to this year’s Western Conference finals against the Dallas Mavericks. Over the first four games of the series, he shot just 29.2 percent from 3-point range. In Game 5, he scored 32 points and shot 8 of 16 from 3-point range to help eliminate Dallas.

“I stuck to the process,” he said, “and eventually I blew the lid off.”

Ahead of Wednesday’s game against Boston, Kerr said a point of emphasis would be to make sure that Thompson got some good looks early that were in rhythm.

As for Thompson’s film study — which he apparently tries to be discreet about — Golden State’s Draymond Green said he had not caught Thompson watching old clips of himself on YouTube.

“The reality is, if I did, we’d probably make fun of him,” Green said. “So it’s probably good that I haven’t.”

To be fair, Thompson does not have much trouble staying grounded on his own. On Tuesday, he recalled where he was about a year ago: working out in an empty arena with Rick Celebrini, the team’s director of sports medicine and performance.

“To be back here on this stage,” Thompson said, “you’ve just got to remind yourself to keep working because it’s a blessing and really an honor to be here.”