After last week's disappointing performance against Japan, the head coach told his Ireland squad to improve their game.
Ireland responded right away.
The Irish side had struggled late against the All Blacks and taken most of the match to find their rhythm versus Japan.
Nevertheless, against the Wallabies, they began powerfully, with the talented back excelling brightest during a comprehensive victory that represented Ireland's finest display of the season.
Making his debut test match start at full-back, Hansen registered a three tries, competed brilliantly for high balls and performed exceptionally against the nation of his birth.
"Look, I've experienced a pretty challenging run with injuries really," Hansen stated.
"I missed being in this team, I know there's considerable talk about me not exactly being raised here and I wasn't raised here, but I adore this team and this seems like home.
"Any time I get to play for the national team it's a honor, if you fail to deliver a good showing you may not receive that privilege again.
"My entire focus this period was to go out and do what I can do."
After twenty-eight appearances on the wing, the player was entrusted the full-back position for the initial time with several teammates unavailable.
In his case, it was simply a case of picking up where he finished during the warmer months.
The 28-year-old had been in superb form before physical issues disrupted his aspiration of making the international team.
Having come back recently, he developed a lower body injury that made him unavailable for previous matches.
The coach had indicated that the player was especially determined and these turned out to be not empty words as the ex- provincial player gave his coach a welcome selection dilemma for future games.
"So my initial reaction were, 'You need to perform well in those two colored shoes!'," said the coach, alluding to Hansen's choice to wear mismatched footwear.
"In fact I believed that was appropriate but apparently Hansen just made that himself regardless. So he's attracted attention to himself before he's even begun.
"I told to him before the game, 'Good players don't need excuses, they can perform and just play naturally, you can get the man of the match if you choose,' and he responded, 'Yeah, I concur.'
"Therefore he's that type of player, he trains thoroughly, he's has a excellent approach to get across his preparation and thus that's why he slotted right into the team and he was able to be himself due to that."
The player's efforts also received praise from the rival coach, who remarked he was the "exceptional opposition player" on the evening.
"I thought he was outstanding, his knowledge showed to the fore," said the ex- national manager.
"Unfortunately, Mack was likely the standout Australian player on the field. He's has a great ability and he's such a good contender."
Pressed about what makes Hansen a strong fit at the number 15 position, Farrell continued: "Showing up in the middle of the field is a trait that he demonstrates from the flank regardless, but I suppose he's better in position for that frequently.
"His aerial play was brilliant, wasn't it? I believed we didn't get bored of executing the correct thing and that was putting the possession again on them to gain field position.
"The reason that was the right strategy to do is since it's the players of Mackie who was getting the balls returned, and additional players, so [it's] pretty pleasing."
Beyond Hansen, there were multiple positives for Farrell.
Another player was outstanding on his comeback to the fly-half jersey, the set piece and line-out functioned smoothly and different player did not appear out of place in his debut appearance in the forwards.
But perhaps most satisfying for the manager was the team bookending the match with two strong periods.
Hansen's first two tries occurred in the opening eleven minutes while additional players registered in the closing stages after the opposition had scored, ensuring the Irish side finished on a high.
"I thought we truly performed freely and attacked the match right from the beginning," said Farrell.
"How we handled numerous aspects during the game, especially the opposition responding just before the break and reorganizing ourselves and producing a performance like we achieved in the second half, I thought as far as territory and being across the majority of our strategy in that second half was truly pleasing."
The strength of South Africa are next up for Ireland, in what might be viewed as an unofficial conclusion to last year's tied two-Test series on rival territory.
Farrell's side will need to reach another standard to beat the consecutive title holders, but the recent defeat of the Wallabies was a important advancement in the right direction after an disappointing start to their fall campaign.
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