The Olympic and Paralympic sprinter, who faces life in prison if convicted of murdering Reeva Steenkamp, says he shot the 29-year-old model in a tragic accident, firing at what he thought was an intruder hiding behind a locked toilet door.
The athlete has broken down numerous times during the 22-day trial, including retching into a bucket. He burst into tears again on Monday morning when recounting the moment he screamed at what he thought was a burglar, prompting the judge to call a 30-minute adjournment.
Get the fuck out of my house! Get the fuck out of my house! a trembling Pistorius said when asked to state precisely what he screamed at the perceived intruder.
He then burst into tears as family members in the public gallery rushed to comfort him.
Towards the end of the day, he again began to cry when answering questions about the immediate aftermath of the shooting.
State prosecutor Gerrie Nel, whose reputation as one of South Africas toughest attorneys has earned him the nickname The Pitbull, said the athlete was just putting on an act to avoid having to answer his questions.
Nel questioned why Pistorius would get upset when being asked about whether he did or did not open doors leading from his bedroom to a balcony to shout for help minutes after the shooting.
I cannot see how that can cause you to be emotional because you cannot remember how to open a door. Were not talking about Reeva, Nel said, referring to previous breakdowns, which have usually been when he describes the shooting.
Youre not using your emotional state as an escape are you Nel said, raising his eyebrows and shaking his head.
The murder trial has captivated South Africa and millions of athletics fans around the world who viewed Pistorius, known as the Blade Runner because of the carbon-fibre prosthetics he uses on the track, as a symbol of triumph over adversity.
His disabled lower legs were amputated as a baby but he went on to achieve global fame, winning Paralympic gold medals and reaching the semi-finals of the 400 metres in the 2012 London Olympics against able-bodied athletes.