After meticulously dissecting every movement Oscar Pistorius claims he made in the early hours of Valentine's Day last year, the state's chief prosecutor declared the runner's version "so improbable that nobody will ever think it's reasonably possible".
"Your version is a lie," Gerrie Nel said simply on Thursday.
The prosecutor used the 20th day of the case to hammer away at the athlete's credibility, accusing him of being a liar, tailoring his evidence, and blame-shifting onto everyone else instead of accepting responsibility for his actions.
He also articulated the specifics of the state's case for the first time, saying he will prove that the screams heard by witnesses in the lead up to the shooting came from Reeva Steenkamp as she ran away from the Olympian in a row.
"I will build my case to say that when you got up, there was an argument and she ran away screaming," Mr Nel said.
"It's not true, my lady," said the athletic track star.
Under meticulous cross-examination, Mr Nel forced Pistorius to be far more detailed about his account than ever before, probing the athlete to give details never before articulated.
The court heard Pistorius claim he awoke in the early hours of Valentine's Day 2013, probably because of the humidity, to find his model girlfriend was beside him.
Ms Steenkamp, also awake, asked: "can't you sleep, baba?" to which he replied no.
Pistorius told the court he then got up from his position on the left-hand side of the bed and walked without his prosthetics to the other side of the bed closest to the balcony, from which he brought in a fan, closed the sliding door and drew the curtains.
At this point, he would have been no more than a metre from Ms Steenkamp.
However, he maintains the model did not say a word, and he didn't see her get up and move towards the bathroom.
Somewhat incredulously, Mr Nel zeroed in on his actions, repeatedly asking how that was possible.
Pistorius claimed it was "pitch black", he had his back to the bed, and "the fans were blowing in my face".
However, Mr Nel pointed out that there was clearly enough light for the athlete to be able to see Reeva's denim jeans on the floor of the bedroom, because the next thing he said he did was pick them up and cover the LED light on an amplifier, plunging the room into "total darkness".
In a police crime scene photo shown to the court, the bed's duvet is lying on the floor, and Mr Nel asked how it got there.
Pistorius blames police for moving it; saying when he got out of the bed the duvet was on it, adding that it was covering the bottom part of Reeva's legs.
"Ah, so (there was enough light that) you saw that," the prosecutor commented.
Mr Nel then secured an acceptance from Pistorius that Ms Steenkamp must have rolled across onto the athlete's side of the bed to walk toward the bathroom, because if she'd got out on the righthand side he would most certainly have seen her.
In the same photo, Mr Nel also highlighted that the curtains were about a metre apart.
If the curtains were not closed, as depicted in the picture, Pistorius should have been able to see inside the bedroom when he heard the noise and know his girlfriend was not in bed.
"You see Mr Pistorius, your version is a lie. You never closed those curtains … that door was open when you and the deceased had an argument," Mr Nel said.
"(The fan) was never moved – that door was open when you and the deceased got into an argument. The fan was there, the duvet was there, the curtains were open."
"No, my lady," he said.
After examining other evidence, Pistorius then conceded that for his version to be correct, a police officer must have had to move a fan, the duvet and open the curtains after the incident.
"Keep trying, Mr Pistorius, it's not working," Mr Nel thundered as the day's evidence drew to a close.
"Your version is so improbable that nobody will ever think it's reasonably possible, it's so improbable."
Pistorius said he was telling the truth.
Earlier, as the cross-examination inched on, Pistorius made another notable slip, and Mr Nel swooped to accuse him of mixing up his lies.
Asked about an incident in 2012, when a handgun was fired in a crowded Johannesburg restaurant, he insisted that he had never put his finger on the weapon's trigger.
He admitted handling the gun, but said it just "discharged" in his hands as he was trying to ensure it was safe.
"I didn't have time to think," he said.
Mr Nel pounced immediately: "Ahh, so that's one of your defences."
He was referring to the athlete's evidence from the previous day, in which he used the same words to describe the shooting of Ms Steenkamp, believing she was an intruder in his toilet door.
The prosecutor also accused Pistorius of "blaming everybody else but himself" as Mr Nel honed in on its portrayal of him as reckless, self-obsessed and controlling.
In what one legal analyst later described as a "rather desperate" measure, Pistorius even tried to shift blame for discrepancies in his version onto his own legal team.
Mr Nel also took the double-amputee to task over his trembling apology on the first day of his evidence-in-chief, asking if he had "felt better" afterward, suggesting it had been a narcissistic move to do it in front of the world's cameras.
"I don't think I could feel better, but I haven't had the opportunity to apologise to them, it's something I wanted to do for a very long time and it's the right thing to do," he said.
The case continues.