Following their previous disappointing performance against Japan, the head coach challenged his Irish team to step up their performance.
The team listened right away.
The Irish side had faded late against the All Blacks and required most of the match to get going versus Japan.
Nevertheless, facing Australia, they started powerfully, with the talented back excelling brightest during a 46-19 victory that marked the team's best performance of the season.
Making his first test match appearance at the number 15 position, the player scored a three tries, competed excellently for high balls and performed exceptionally against the nation of his origin.
"Look, I've had a fairly challenging run with injuries really," the athlete commented.
"I longed for being in this team, I know there's considerable discussion about me not exactly being raised here and I wasn't raised here, but I adore this group and this feels like home.
"Any time I get to represent for Ireland it's a honor, if you don't put in a good showing you may not receive that privilege again.
"My whole approach this week was to go out and perform what I could do."
After 28 appearances on the flank, the player was given the full-back position for the initial time with multiple players injured.
In his case, it was essentially a matter of continuing where he left off during the warmer months.
The 28-year-old had been in superb condition before injury ended his aspiration of making the Test squad.
After come back last month, he suffered a lower body injury that ruled him out for earlier fixtures.
Farrell had indicated that Hansen was particularly determined and these turned out to be not hollow statements as the ex- provincial player gave his manager a welcome team dilemma for upcoming games.
"Well my initial thoughts were, 'You need to perform well in those different coloured shoes!'," commented Farrell, alluding to Hansen's choice to wear different boots.
"In fact I thought that was appropriate but apparently Mack just made that himself regardless. So he's drawn attention to himself before he's even begun.
"I said to him before the match, 'Good athletes require no justifications, they can get on with it and just be themselves, you can get the player of the game if you want,' and he went, 'Yes, I agree.'
"Therefore he's that kind of performer, he trains well, he's got a excellent approach to get across his preparation and thus that's why he slotted right back in and he was capable to perform naturally because of that."
Hansen's performance also earned praise from the rival coach, who remarked he was the "exceptional Australian performer" on the evening.
"I thought he was outstanding, his knowledge was evident to the front," said the ex- national coach.
"Unfortunately, Hansen was likely the best Australian performer on the pitch. He's got a great skillset and he's such a good contender."
Pressed about what enables Hansen a good option at full-back, Farrell added: "Showing up in the center of the field is something that he demonstrates from the flank anyway, but I suppose he's better in position for that more often.
"The player's aerial play was excellent, wasn't it? I thought we persisted of doing the correct approach and that was putting the possession again on them to secure territory.
"Why that was the right thing to do is since it's the likes of Mackie who was securing the balls returned, and other teammates, so [it's] quite satisfying."
Beyond the star performer, there were numerous encouraging aspects for the coach.
Sam Prendergast was outstanding on his return to the number 10 position, the set piece and line-out operated smoothly and different teammate did not appear out of place in his first appearance in the forwards.
But perhaps more satisfying for the manager was the team bookending the match with multiple impressive periods.
The player's first two scores came in the opening eleven moments while additional teammates scored in the closing exchanges after the opposition had crossed, guaranteeing the Irish team concluded on a positive note.
"I thought we really let ourselves go and attacked the match right from the beginning," said the coach.
"The way we managed various aspects throughout the game, particularly the opposition coming back just before half-time and regathering ourselves and giving a performance like we achieved in the later stages, I believed as far as field position and being across the majority of our game in that second half was truly pleasing."
The strength of South Africa are awaiting for Ireland, in what might be viewed as an informal conclusion to the previous season's tied multiple match contest on rival territory.
Farrell's side will require to reach another standard to beat the consecutive world champions, but Saturday's defeat of the Australian team was a significant step in the right direction after an disappointing start to their autumn campaign.
Seasoned blackjack enthusiast and strategy coach with over a decade of experience in casino gaming.