Tuohy believes a Wales side brimming with British and Irish Lions talent will be the acid test and the Ulster second row insisted there will be "bigger steps" than Scotland, whom Ireland swatted aside 28-6 in Dublin on Sunday.
But he warned the Irish must heed the cautionary tale of last season's abortive Six Nations, and has warned his team-mates to fight off another false dawn.
Ireland won 30-22 in Wales in their opening Six Nations match last season, only to slump to four straight defeats, a capitulation which cost Declan Kidney his job.
Tuohy acknowledges that Ireland must steel themselves to double their championship win tally when Wales visit Dublin on Saturday.
He said: "There are bigger steps to come [than Scotland]. We have tough games coming up - England away, France away - but these are teams we can mix with, so we're looking forward to it.
"Wales will be a different kettle of fish. They have had a bit of a 'feeler' game against Italy.
"We won the first game last year and we all know how that ended up, so it's important for us to back up the first week; become a consistent international team, that's what we've talked about.
"The six-day turnaround isn't ideal but we just have to get on with it and roll our sleeves up. Wales are going for the hat-trick, they've got Lions all over the park, so it will be notched up another level. It's important for us to match that physicality and intensity, and then try to go beyond it."
Tuohy slotted in for O'Connell at the last minute on Sunday, the Munster talisman having been laid low by a chest infection on Saturday night. However Joe Schmidt, the Ireland coach, is confident that O'Connell will be fit for Wales.
Tuohy has helped Ulster register a 100% record in a Heineken Cup pool stage for the first time. With Leinster and Munster's decorated European past to boot, he admitted Ireland have shared fans' frustration in the failure to transfer club success to the international arena.
Wales duty tends to bring the best out of their leading players, and Tuohy challenged Ireland to follow their lead.
"As soon as they put on that red jersey they turn into a different beast. They really do lift the intensity when they're playing for Wales. They are lit up with Lions, coming off a great tour, they'll be high on confidence.
"But it's important for us to stick to what we know, and what we know works for us.
"I think it's always been frustrating from a fan's point of view that the provincial sides are doing so well but then we've struggled to get consistency with Ireland. People were wondering why, if it goes so well with the provinces, can't they do it for Ireland?
"That's something we're mindful of. To be a consistent team is tough, but the more time you spend together you get to know each other a little bit better."