At Green Bay in Week 11, in the game’s final 30 seconds, Johnston couldn’t secure a ball that would have put the Chargers at least in range for a tying field-goal attempt.

One fourth-down incompletion later, their 23-20 loss was official and an underwhelming first NFL season for Johnston crept painfully forward.

On Tuesday, after the team’s latest spring practice, Johnston said he has rewatched the play in recent months as a means of motivation, especially on days when he’s searching for a spark.

“[I’ll] pull it up real quick,” he explained, “kind of got mad at myself again.”

Johnston called the drop “just straight-up unacceptable” as he tries to rebound under the Chargers’ new coaching staff and in a vastly altered wide receiver environment.

Veterans Mike Williams and Keenan Allen left the team in March as salary cap casualties. The Chargers signed DJ Chark in free agency and drafted three wide receivers — Ladd McConkey, Brenden Rice and Cornelius Johnson.

One of the top holdovers at the position along with Joshua Palmer, Johnston finds himself with an inviting opportunity to prove he was worthy of being the 21st player taken overall in the 2023 draft.

His need to improve has been boosted by the memory — and images — of that November day in Wisconsin, where Johnston’s inconsistent play and doubted hands were on full display.

He said he has been driven by a desire to avoid having his situation “just wind down into a game like that, which obviously I do not want again.” Targeted six times that afternoon, Johnston finished with just two catches for 21 yards.

Even with Williams missing the final 14 games and Allen the last month because of injuries, Johnston’s rookie performance remained underwhelming. His 38 receptions went for 431 yards and a pair of touchdowns.

“My expectations never change for myself,” Johnston said. “Even through the bad games I had last year, I was never like, ‘Maybe I can’t do it.’ I still hold myself to a high standard.”

With Williams and Allen elsewhere, the Chargers would love to have Johnston reassert himself as a rising prospect. But what remains unclear is how much patience the team’s new regime will have for a top draft pick it inherited.

Wide receivers coach Sanjay Lal was with Seattle last year and studied Johnston extensively leading up to the draft. The Seahawks were eyeing a receiver, too, and selected Jaxon Smith-Njigba at No. 20.

“It’s not fair to look back,” Lal said when asked about Johnston’s uneven first year. “Looking forward, he moves as well as any receiver I’ve seen. So the potential is very high.”

Explaining that Johnston has “a lot of juice,” Lal said the Chargers have been working on his body positioning. At 6-foot-4, 215 pounds, Johnston possesses the necessary dimensions.

In fact, Lal said he specifically has been showing Johnston tapes of Seattle’s DK Metcalf, a player known for his body usage. A much more physical receiver than Johnston, Metcalf is 6-4, 235 pounds.

What Lal said he isn’t doing is dwelling on Johnston’s 2023 season. Since he wasn’t with the Chargers then, Lal said there’s no point in trying to figure out what went wrong under circumstances unfamiliar to him.

“I don’t know the context,” Lal said. “To take a player back to that, especially if it’s a negative, I don’t see any purpose going forward. I see, ‘This can be improved.’ I know the drills to improve it. I’m going to implement those. I don’t need the context.”

Johnston said his focus this offseason largely has been focus. He said he wasn’t detailed enough in his approach to catching the ball last year. He insisted the experience hasn’t dented his confidence.

He also used terms like “first-year jitters” and “anxiousness” in describing his sometimes disconnected partnership with Justin Herbert.

“Instead of being on the quarterback’s time,” Johnston said, “I was trying to rush it and be on my time.”

Four wide receivers were taken in the draft’s first round in 2023 — one after another from picks 20 to 23. After Smith-Njigba and Johnston, Zay Flowers went to Baltimore and Jordan Addison to Minnesota.

Among the foursome, Johnston finished last in catches, yards and touchdowns, and the numbers weren’t especially close.

The opportunity before him in 2024 is certainly enticing and encouraging, the Chargers looking to their younger wideouts for production.

“It’s different for sure,” Johnston said of Williams and Allen being gone. “But that’s just them making room for us to step up [and] grow up a little bit quicker as a leader.”