Following last week's disappointing showing against the Japanese team, the head coach told his Irish team to improve their performance.
Ireland responded right away.
Ireland had faded in the final stages against the All Blacks and required considerable time to get going versus Japan.
Nevertheless, against Australia, they started strongly, with the talented back excelling most prominently during a comprehensive victory that marked the team's best performance this year.
Making his debut test match appearance at full-back, the player scored a hat-trick, competed brilliantly for aerial challenges and played outstandingly against the nation of his origin.
"Look, I've had a fairly challenging run with injuries really," Hansen commented.
"I longed for being in this team, I know there's considerable discussion about me not exactly being born here and I didn't grow up here, but I adore this team and this seems like family.
"Whenever I get to represent for Ireland it's a honor, if you don't put in a performance you may not receive that privilege again.
"My whole focus this week was to take the field and do what I can do."
Following twenty-eight caps on the flank, the player was entrusted the number 15 position for the first time with multiple teammates injured.
In his case, it was essentially a case of picking up where he finished during the summer.
The experienced player had been in excellent form before injury disrupted his aspiration of joining the Test team.
Having come back recently, he suffered a foot problem that made him unavailable for previous fixtures.
The coach had indicated that Hansen was particularly motivated and these turned out to be not empty words as the former club player gave his coach a positive selection dilemma for upcoming matches.
"Well my initial reaction were, 'You need to play well in those different coloured shoes!'," commented Farrell, alluding to the player's decision to sport different footwear.
"Actually I believed that was appropriate but apparently Mack just made that personally anyway. So he's drawn notice to himself before he's even started.
"I said to him before the game, 'Excellent athletes require no justifications, they can perform and just play naturally, you can win the player of the game if you want,' and he went, 'Yes, I agree.'
"Therefore he's that type of performer, he trains well, he's has a excellent approach to get across his preparation and thus that's why he fitted straight back in and he was capable to perform naturally because of that."
The player's efforts also received praise from the opposing coach, who remarked he was the "exceptional Australian player" on the night.
"In my view he was outstanding, his experience showed to the front," commented the ex- national manager.
"Regrettably, Mack was likely the standout opposition player on the pitch. He's got a excellent skillset and he's such a good competitor."
When asked about what enables Hansen a good fit at the number 15 position, the coach continued: "Appearing in the middle of the field is something that he demonstrates from the flank anyway, but I suppose he's more in place for that more often.
"His aerial play was excellent, don't you think? I thought we didn't get bored of doing the right thing and that was placing the possession again on them to secure territory.
"The reason that was the correct strategy to do is because it's the players of Hansen who was getting the balls returned, and other teammates, so [it's] pretty satisfying."
Outside the star performer, there were multiple positives for Farrell.
Sam Prendergast was excellent on his comeback to the number 10 jersey, the scrum and throw-in operated smoothly and different teammate did not look uncomfortable in his first start in the front row.
But perhaps most pleasing for the manager was Ireland bookending the game with two strong spells.
The player's first two scores came in the first 11 minutes while additional players registered in the closing stages after the other team had crossed, guaranteeing the Irish side finished on a high.
"In my opinion we truly let ourselves go and attacked the game right from the beginning," said the coach.
"How we managed numerous elements during the game, especially the opposition coming back just before the break and reorganizing ourselves and giving a display like we achieved in the second half, I believed as far as territory and being familiar with most of our strategy in that second half was truly satisfying."
The might of the Springboks are next up for Ireland, in what might be viewed as an informal conclusion to last year's tied multiple match series on rival soil.
The coach's side will require to reach another level to defeat the consecutive world champions, but the recent defeat of the Wallabies was a significant step in the correct path after an disappointing start to their autumn campaign.
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