Paul O'Connell believes Gregor Townsend has created the strongest Scotland team he will have ever faced either as player or coach.
Scotland stunned England 11-6 at Twickenham to kick-start the Six Nations and the former Munster and Ireland lock also hailed head coach Townsend for adding an under-appreciated physical element to his team's exciting attacking play.
"There's no doubt Scotland are an excellent side," said O'Connell.
"I think any team that's coached by Gregor Townsend always attacks really well, but going back to his Glasgow days they always have an incredibly physical edge.
"You think sometimes if a coach is into attack his teams won't have a physical edge, but every single Glasgow team I played back in the day were excellent attacking sides but they were physical as well. And it's the same with this Scotland side now.
"So much of the good attack in the Autumn Nations Cup and the start of the Six Nations has come from Scotland. And then they are very, very physical as well.
"It was a fantastic performance by them against England in the first game, an excellent set-piece performance that laid a real solid foundation for them to go on and win.
"I think it's the best Scottish team I've ever gone up against, as a coach or a player.
"They're very well coached, very physical and they've got some real X-factor players as well, Finn Russell to name one and Stuart Hogg just to name another.
"So I think they are in a very, very good place and we're very aware of the challenge."
O'Connell's comments will prove another boost for Townsend's chances of making Lions boss Warren Gatland's coaching team for the summer Test series against South Africa, with the Scotland chief heavily favoured for a backroom role.
Josh Van Der Flier must pass head-injury return to play protocols to contest selection for Sunday's Murrayfield trip, but otherwise Ireland have a fully fit squad.
Andy Farrell's Ireland will be itching for top form and victory in Scotland, having lost out 21-16 in Wales and 15-13 to France in Dublin.
The 48-10 win over callow Italy in Rome on February 27 offered some respite and plenty of cheer, but O'Connell knows full well that the final two fixtures – against Scotland and England – pose an entirely different challenge.
"These next two weeks against a resurgent, confident Scottish side, and an English side we've struggled against in recent months and years, it's a real tough challenge now, the last two weeks," said O'Connell.
"I think we've taken confidence from some of the things we've done in the last three games; we've probably been unlucky in some regards and we haven't helped ourselves in other regards.
"We've probably given sides a leg-up when we've played them at times and that's something that we just can't afford to do going forward in the next two weeks.
"You have to be hard to beat, you can't give things away to teams.
"Unfortunately we've done that a little bit and the next two weeks that's one of the most important parts of what we have to deliver.
"We can't give things away, we can't give teams a leg-up, because this Scottish team will take advantage of that."