MINNEAPOLIS — A police officer approached a car with George Floyd in the front seat, and Mr. Floyd started to panic. While officers ordered him to spit out a pill he was trying to swallow, he repeatedly begged them not to shoot him.

Within seconds, one of the officers had his gun drawn and Mr. Floyd was being pulled out of the car and handcuffed.

The body-worn camera video of that scene was shown for the first time on Tuesday to jurors in the trial of Derek Chauvin, the former police officer charged with murdering Mr. Floyd. The episode was strikingly similar to the day Mr. Floyd died. But it had been taken a year before.

As the defense began its case after 11 days of testimony against Mr. Chauvin, the video was the first exhibit introduced and signaled a key strategy: shifting the jurors’ focus to Mr. Floyd’s use of illicit drugs.

Mr. Chauvin’s lawyer, Eric J. Nelson, presented the video of the May 2019 arrest and questioned the paramedic who treated Mr. Floyd that day. He asked a woman who was with him the day he died about how Mr. Floyd fell asleep in the car and was difficult to rouse. He reviewed the signs of excited delirium, a condition often attributed to using stimulants.

Other planks of the defense emerged as well, including suggestions that the bystanders who tried to intervene were threatening and that Mr. Chauvin’s behavior was reasonable in the circumstances.

A Minneapolis Park Police officer who responded to the scene on May 25, 2020, the day Mr. Floyd died, testified that the bystanders were aggressive enough to make him fear for the other officers’ safety. A policing expert said the period of time when Mr. Chauvin knelt on Mr. Floyd’s neck was not only justified but did not even qualify as force. Each line of questioning was designed not so much to persuade the jury, but to sow the seeds of reasonable doubt.

The judge, Peter A. Cahill, has tried to bar a common defense tactic, blaming the victim. He has strictly limited testimony about Mr. Floyd, saying that his past acts and state of mind were not relevant to the case.

But the defense has tried to expose jurors to Mr. Floyd’s history of involvement with the police, and arguments over how much of the May 2019 arrest jurors would see began well before the trial.

Mr. Nelson said that arrest showed a pattern of behavior in which Mr. Floyd responded to the police by panicking, implying that he faked his response.

“This goes to the very nature of this case and why public perception is what it is,” Mr. Nelson said in court a few weeks ago. “The things that he is saying. ‘I can’t breathe.’ ‘I’m claustrophobic.’ Calling out for his Mama.”

The judge did not buy that argument, and initially barred any mention of the incident. He changed his mind after a second search, in January, of the squad car used on the day Mr. Floyd died turned up half-chewed pills of methamphetamine with Mr. Floyd’s DNA and saliva on them. He said that showed similarities between the two arrests, but he allowed the jury to see only about 90 seconds of the 2019 video.

“This evidence is being admitted solely for the limited purpose of showing what effects the ingestion of opioids may or may not have had on the physical well-being of George Floyd,” Judge Cahill told the jury on Tuesday before the video was shown. “This evidence is not to be used as evidence of the character of George Floyd.”

The video showed Mr. Floyd being slow to respond to commands from the police, and the officer who wore the body camera reaching to put Mr. Floyd’s hand on the dashboard. “It escalated real quick,” said the officer, Scott Creighton, who is now retired and who was the day’s first witness.

The prosecution has tried to engender empathy for Mr. Floyd’s struggle with opioid addiction, presenting testimony that he had tried to stop using. On Tuesday, the paramedic who was called to the precinct to treat Mr. Floyd in 2019 said he told her that not only had he taken an opioid painkiller as the officer approached the car, but that he had been taking them every 20 minutes.

Dan Herbert, a defense lawyer in Chicago who specializes in representing police officers, said the defense accomplished its goals in presenting the 2019 arrest. “What Nelson needs to do is show a side of George Floyd that is different from the poor individual that suffocated before everyone’s eyes on video,” he said. “He was lucky and didn’t die in that incident in 2019 — he wasn’t as lucky in 2020, that’s the strategy there.”

But the evidence could backfire because it showed an aggressive, profanity-laden approach by the police officers, and because unlike in 2020, Mr. Floyd was given medical assistance and survived the encounter.

“I don’t think Nelson scored a point at all,” said Albert Goins, a retired Minneapolis defense lawyer who represented the family of Jamar Clark, a Black man killed by the Minneapolis police in 2015. “Not only did Nelson’s use of the 2019 incident not land any blows, it raised the issue of the arbitrary practice and history of the Minneapolis Police Department in stopping its Black citizens.”

The defense spent the most time on Tuesday on testimony from Barry Brodd, the first witness to explicitly defend Mr. Chauvin’s actions.

Mr. Brodd, a former police officer and expert on self-defense, said that putting Mr. Floyd handcuffed in the prone position on the street did not qualify as force because no pain was inflicted.

“I felt that Derek Chauvin was justified, and was acting with objective reasonableness, following Minneapolis Police Department policy and current standards of law enforcement, in his interactions with Mr. Floyd,” he said.

Mr. Brodd made statements that have been used before to defend officers accused of killing a Black man. He mentioned Mr. Floyd’s size and muscular build, and said that some suspects who are high on drugs “don’t feel pain” and can exhibit “superhuman strength,” said to be a sign of a condition called excited delirium that is often used to explain deaths in police custody.

On cross-examination, Steve Schleicher, one of the prosecutors, got Mr. Brodd to acknowledge that under Minneapolis Police Department policy a restraint is considered a use of force, and that a reasonable officer would abide by department policies.

Mr. Brodd acknowledged that he had listened to the videos in which Mr. Floyd expressed pain, saying, “Everything hurts.” But, Mr. Brodd said, he didn’t “note it.”

While Mr. Brodd challenged days of testimony on accepted police practices presented by the prosecution, not all the witnesses on Tuesday were friendly to the defense. Shawanda Hill, another witness, made it plain through her facial expressions that it was not her choice to testify.

Ms. Hill ran into Mr. Floyd at Cup Foods, the convenience store where he spent the $ 20 bill that was reported to the police as counterfeit, and he offered her a ride. Once they were in the parked car, she said, Mr. Floyd kept falling asleep and was difficult to rouse. When police officers approached the car, she said, she woke him.

“He instantly grabbed the wheel and he said, ‘Please, please don’t kill me,’” she said.

Another witness was Peter Chang, a Minneapolis Park Police officer who responded to the scene and was asked to watch Mr. Floyd’s car. As he did that, he said, he became concerned for the safety of the officers who were interacting with Mr. Floyd. “The crowd was becoming more loud and aggressive,” he said.

Officer Chang’s body camera video showed long minutes during which Ms. Hill and another of Mr. Floyd’s associates, Morries Lester Hall, waited on the sidewalk, unable to see what was happening to Mr. Floyd. When the ambulance carrying Mr. Floyd began to pull away, they asked if they could retrieve his phone from the car.

“He’s already gone,” Mr. Chang told them. “He doesn’t need his phone.”