Oscar Pistorius's lawyers at his murder trial tried to roll back the prosecution's momentum b ut the prosecutor sharply questioned a forensic expert for the defence.
Following the tough cross-examination of Pistorius that lasted five days, his defence attempted to reassert his story that he killed his girlfriend by mistake, but the prosecutor strongly challenged the credentials and findings of the expert witness.
Roger Dixon, a forensic geologist at the University of Pretoria and a former policeman, contradicted parts of the evidence given by a police ballistics expert and the state pathologist who examined the body of Reeva Steenkamp, fatally shot last year by Pistorius.
But Mr Dixon acknowledged that he did not have expertise in some of the areas in which he was giving evidence, including sound, light and ballistics.
Mr Nel was sometimes sarcastic while questioning Mr Dixon, subjecting him to the same gruelling scrutiny with which he challenged Pistorius, who often fumbled for answers while in the witness box.
Mr Dixon offered a different version for the order of the shots that killed Ms Steenkamp in an attempt to back up Pistorius's version of a mistaken shooting and rebuild his case after the Olympic athlete's shaky evidence.
He said it was his opinion that Ms Steenkamp was hit in the hip and the arm in quick succession by the first two of four shots while she was standing close to the door, and indicated he believed she may have had her right arm extended and maybe her hand on the door handle, as if she was about to open the door through which she was shot.
The defence was using Mr Dixon's evidence to try to cast doubt on the prosecution's version that Ms Steenkamp fled to the bathroom and was hiding in the toilet during a fight with Pistorius in the pre-dawn hours of February 14, 2013.
Mr Nel has said that the double-amputee athlete shot Ms Steenkamp through the door as she faced him and while they were arguing.
Pistorius, 27, is charged with premeditated murder over Ms Steenkamp's shooting death and faces 25 years to life in prison if convicted on the charge. He claims he shot the 29-year-old model by mistake thinking she was a dangerous intruder in the toilet about to come out and attack him.
Mr Dixon also said he took part in audio tests conducted by experts for the defence that showed the sounds of gunshots and of a cricket bat hitting a door were similar and could be confused.
The difference is important because several neighbours have said that they heard Ms Steenkamp scream before shots on Valentine's Day last year, backing the prosecution's case that there was a fight before Pistorius shot his girlfriend with his 9mm pistol.
Pistorius's defence says the witnesses are mistaking the sequence and they heard Pistorius screaming in a high-pitched voice for help before breaking the door open with the bat to get to Ms Steenkamp.
In a cutting statement on Mr Dixon's finding regarding Ms Steenkamp's wounds, Mr Nel said to Mr Dixon: "I use the word 'finding' very loosely."
Mr Nel also questioned Mr Dixon's role in the audio test involving the sounds of gunshots and a bat that was played by defence lawyers during Mr Dixon's evidence.
"Your expertise (in the audio test) was wielding the cricket bat?" Mr Nel asked Mr Dixon sarcastically.
Mr Dixon replied: "My part of that test was to wield the cricket bat to produce the sound."
On questioning by Mr Nel, Mr Dixon conceded the tests had to be done a second time because of problems with the first test, and they were recorded by a music producer who had no experience in recording gunshots.
Earlier, Judge Thokozile Masipa ruled that proceedings will adjourn for more than two weeks after Thursday and resume again on May 5.