Following their previous disappointing performance against Japan, the head coach told his Ireland team to improve their performance.
The team responded immediately.
The Irish side had faded late against the All Blacks and taken most of the match to find their rhythm versus Japan.
Nevertheless, against the Wallabies, they started powerfully, with Mack Hansen shining most prominently during a comprehensive victory that marked Ireland's best performance this year.
Making his debut test match start at full-back, Hansen registered a three tries, contested excellently for aerial challenges and played exceptionally against the country of his birth.
"You know, I've experienced a fairly challenging run with injuries really," Hansen stated.
"I missed being in this team, I understand there's considerable discussion about me not necessarily being born here and I didn't grow up here, but I love this team and this feels like family.
"Any time I have to represent for the national team it's a privilege, if you don't put in a good showing you may not get that opportunity again.
"My entire approach this week was to go out and perform what I could do."
After 28 appearances on the flank, the player was entrusted the number 15 position for the initial time with multiple players injured.
In his case, it was essentially a case of picking up where he left off during the summer.
The 28-year-old had been in superb form before physical issues ended his aspiration of making the Test squad.
Having come back recently, he developed a lower body problem that made him unavailable for earlier fixtures.
Farrell had suggested that the player was especially motivated and these proved not empty statements as the ex- club player gave his manager a positive selection headache for future matches.
"So my first thoughts were, 'You need to play well in those two coloured shoes!'," commented the coach, referring to Hansen's choice to wear different footwear.
"In fact I believed that was appropriate but it seems Hansen just made that himself anyway. So he's attracted notice to himself before he's even begun.
"I told to him before the match, 'Excellent players don't need excuses, they can get on with it and just be themselves, you can get the man of the match if you want,' and he responded, 'Yeah, I concur.'
"Therefore he's that kind of player, he prepares thoroughly, he's has a great approach to understand his preparation and thus that's why he fitted straight into the team and he was able to be himself due to that."
The player's performance also received commendation from the rival manager, who stated he was the "exceptional Australian performer" on the evening.
"In my view he was outstanding, his knowledge showed to the front," commented the former national manager.
"Regrettably, Mack was probably the standout opposition performer on the field. He's got a great ability and he's such a good contender."
When asked about what makes Hansen a good fit at full-back, Farrell added: "Appearing in the middle of the field is a trait that he demonstrates from the wing regardless, but I imagine he's more in position for that more often.
"The player's aerial play was excellent, don't you think? I believed we persisted of doing the correct approach and that was placing the possession again on them to secure territory.
"Why that was the right thing to do is since it's the players of Mackie who was getting the possessions back, and other teammates, so [it's] pretty pleasing."
Beyond Hansen, there were numerous positives for Farrell.
Another player was outstanding on his return to the number 10 position, the scrum and throw-in functioned effectively and another teammate did not appear uncomfortable in his first appearance in the front row.
But possibly most pleasing for Farrell was the team bookending the game with two strong periods.
Hansen's first couple of scores came in the first eleven minutes while other teammates registered in the final stages after the opposition had scored, guaranteeing the home side concluded on a high.
"I thought we truly let ourselves go and approached the game right from the beginning," said Farrell.
"The way we handled numerous aspects throughout the match, particularly the opposition coming back just before half-time and regathering ourselves and producing a display like we achieved in the second half, I thought as far as territory and being across the majority of our game in that later period was really satisfying."
The strength of South Africa are next up for the team, in what could be viewed as an unofficial conclusion to the previous season's tied two-Test contest on rival soil.
The coach's side will require to reach a higher standard to beat the consecutive title holders, but Saturday's victory of the Australian team was a important step in the right path after an uninspiring start to their fall schedule.
