George Pell is appealing against his convictions for sexual abuse, but prosecutors say the convictions are "unimpeachable" and should be upheld.
Pell, 77, is appealing against a jury's decision to convict him of sexually abusing two choirboys in 1996, and abusing one of the boys again the following year.
He is currently serving a six-year jail sentence for the crimes, but his legal team has presented 13 reasons they say show the convictions should be overturned.
Pell's lawyer, Bret Walker SC, yesterday argued the jury could not have been satisfied of Pell's guilt beyond reasonable doubt.
He argued the offending was impossible because of the robes Pell wore and his location in the church, which was full of people.
Prosecutors today responded to those claims, arguing the guilty verdicts should be upheld.
In written submissions, they argued the jury was entitled to accept the complainant as a reliable and credible witness and that his allegations were not improbable when all the evidence was considered.
"When looking at the whole of the evidence, the integrity of the jury's verdicts is unimpeachable," according to their written submission.
Jury was able to try on robes
Christopher Boyce QC, for the prosecution, told today's hearing the complainant was "a very compelling witness".
"He was clearly not a liar, he was not a fantasist, he was a witness of truth," Mr Boyce said.
He said the complainant's account was supported by the fact he knew the layout of the priest's sacristy where the abuse occurred, a room which was otherwise off limits to the choirboys.
Mr Boyce and the judges discussed the specifics of priests' clothing as Mr Boyce responded to yesterday's argument that Pell's clerical robe could not have been pulled aside to commit the abuse.
That included questions about whether it was possible to use the toilet when wearing the robes.
Mr Boyce said that, whether the robes were lifted up or moved to one side, "the manner in which that could be done is not inconsistent with the complainant's description of what he saw when he was 13".
He said the jury had been given the opportunity to try on the robes to see their manoeuvrability, and suggested the judges could do the same.
Live-stream audio cut after victim named
Mr Boyce began his arguments strongly but soon forced the public live-stream of the hearing to be temporarily dumped when he mistakenly said Pell's victim's name.
Under Victorian law, sexual assault victims cannot be named publicly.
Throughout the hearing, Mr Boyce at times appeared to flounder as the Court of Appeal judges - Chief Justice Anne Ferguson, Justice Chris Maxwell and Justice Mark Weinberg - challenged his arguments.
The judges asked what they should make of the fact the two choirboys did not discuss the abuse, despite remaining friends.
Mr Boyce responded that they would have wanted to "get on with their lives", which consisted of things like playing sport and going to school.
Justice Weinberg said the "best answer" was that it was for the jury to decide whether that created reasonable doubt.
"Precisely," Mr Boyce said.
Justice Maxwell later asked if the risk involved in Pell's offending should be weighed by the judges when deciding if there must have been reasonable doubt he had committed the offences.
"Most people don't take risks that, if they eventuate, will cause them great embarrassment or worse," he said.
Mr Boyce responded: "Some people do."
At the opening of proceedings on the first day of the hearing, Justice Ferguson made clear that if judges asked questions during the hearings, they were not taking a view on the overall case, but "simply testing the argument".
The hearing has been adjourned for a decision to be handed down on a future date.
Pell has indicated he will not seek a reduction to the six-year sentence if the appeal against the verdict fails.