He has been asked by his barrister Barry Roux: "Did you at any time intend to kill Reeva?" His voice stready, he replied: "I did not intend to kill Reeva or anyone else for that matter."
Oscar leaving court on Tuesday after suffering an emotional collapse
The gold-medal winning Paralympian struggled for composure as he described to the court holding his dying girlfriend after shooting her.
"Reeva had already died while I was holding her, before the ambulance arrived so I knew there was nothing more I could do for her," he said.
Oscar has denied the state's accusation that he killed her following an argument, saying that he mistook her for an intruder.
The 27-year-old was asked to explain what he says was a desperate attempt to help the model after firing at her through a toilet door. Prompted by his lawyer, Oscar demonstrated how he struck the door with a cricket bat to reach her.
He has been describing the night he shot his girlfriend
He was also questioned about what his closest neighbours heard on the night of the shooting. His defence is trying to show that they heard him crying for help - rather than Reeva screaming in terror.
During the previous day's evidence on Tuesday the star athlete lost all self-possession and let out great sobs as he spoke of "the moment everything changed", reliving the night she died.
Reflecting his anguish, Oscar's sister Aimee, uncle Arnold and aunt Lois were all crying softly. June Steenkamp, Reeva's mother, who had been composed up until then, buried her hands in her head.
His sister Aimee wept as he spoke of Reeva's final moments
The sprinter recalled conducting a frantic search of the bedroom after realising that his girlfriend was not in bed as he'd thought.
"I retreated to the corner of the bed while talking to Reeva. She didn't respond. I lifted myself onto the bed.
"I felt if Reeva was there. I couldn't feel anything. I thought she had gone down on the floor. I kept my firearm pointing towards the passage. It dawned on me that it could be Reeva in the toilet. I jumped off the bed and tried to see if she was hiding behind the curtain.
"I didn't want to believe that it could be Reeva in the toilet. I was still scared that someone was coming to attack us."
His testimony was too much for Reeva's mother June
He went back to the toilet and pushed the door but it was locked, he added. "I shouted from the balcony for help. Help! Help! Help!"
He said. "I was screaming and shouting at this stage. I was crying out for the Lord to help me. I was crying for Reeva … At that point all I wanted to do was just look inside to see if it was Reeva."
When Oscar became too agitated to continue the judge adjourned the court. After a few minutes his lawyer reported back on the athlete's condition saying that his shirt was wet and he couldn't come back.