With 11 wins from 12 tests, and a season which captured a grand slam and first home win over the All Blacks, Ireland set the bar in 2018 and rightly claimed every accolade for doing so.
This season, though, Joe Schmidt's men have struggled to back up those performances.
Worries from within are now mounting in this, the World Cup year.
Schmidt has been open about the fact his side's confidence was rocked in their opening Six Nations defeat to England in Dublin – going as far to say Ireland are a "bit broken".
Since the bubble burst, Ireland registered away victories over Scotland and Italy but even those lacked the clinical edge they harnessed towards the back end of last year.
On field frustrations are increasingly evident from leading playmakers Jonathan Sexton and Conor Murray. The kicking game and lineout are other areas of concern.
Injuries haven't helped, but after such elevated hopes, public angst and scrutiny continues around the sudden absence of overall cohesion.
With France this weekend in Dublin, before the final round showdown with the as yet unbeaten Welsh in Cardiff, Ireland remain in the hunt for the Six Nations crown.
At this early stage, though, it is clear they have not yet regained anywhere near the same form as last season.
Hansen believes the role of favourites may be a contributing factor.
"I said it at the time when we played Ireland that whoever won that game was going to be viewed as the No 1 team in the world and everyone is going to chase them," Hansen said.
"For us that's something we've been used to. We've been ranked the No 1 team for 112 months now I think but people have seen Ireland as the top dog after they beat us, and that put a massive amount of expectation on the players and coaches.
"Instead of being the hunters they are the hunted and it's different. It's different when you're sitting at the top of the tree. It's a different experience. Not many teams cope with it that well."
This theme is similar with England.
Largely written off for their opening match of 2019, England relished underdog status to stun Ireland.
That performance mixed the destructive power of the Vunipola brothers and Manu Tuilagi with defensive resilience and tactical nous. In one 80 minute effort, they put world rugby on notice of what they can produce when at full strength.
Three weeks later, while venturing to Cardiff, the favourites tag didn't sit so comfortably as Eddie Jones watched his men crumble under second half pressure.
Warren Gatland didn't miss when he then questioned England's ability to turn up and win big games.
As we etch closer to Japan, this thread of who can handle the pressure of being cast as favourites is sure to continue.
"They're all capable of knocking off a big team," Hansen said. "We've seen that with Ireland. They were favourites going into the tournament and they've been beaten by England. Then all of a sudden England were favourites to win the tournament, now they've been beaten.
"France should've beaten Wales in the first game so it's a pretty even contest all round. You've got to turn up and play well if you want to be in it.
"It's different to the Super competition; it's different to Sanzaar test matches but it's still really good rugby. There's been some brutal tests. All of the Home Nations, plus France, and there's been some improvement in Italy too."
Hansen, meanwhile, brushed off concerns closer to home around the stuttering start to the season from New Zealand Super Rugby teams.
The Blues are winless after three games; the Chiefs reeling from defeats to the Brumbies and Sunwolves while the Highlanders, missing Aaron and Ben Smith, lost to the Rebels in Melbourne last week.
Australian sides have certainly improved but with rest and rotation of All Blacks in full swing ahead of the World Cup, the depth of New Zealand rugby is being severely tested.
"I don't get too carried away with Super Rugby until halfway through then you start to get a clearer picture about who is doing what.
"I've said all along Australia have got plenty of good rugby players and so have we.
"There's a lot of stuff happening around people getting opportunities because people haven't come back in until late after everyone, including the Super Rugby coaches and us, have deemed that's the way we should treat our All Blacks who don't finish their season until December.
"You've got to give them a break, and there's always a consequence for that break. To say New Zealand teams aren't playing well, I don't think that's a fair reflection of what's actually happening."