The All Black legend led the Azzurri to only their second-ever 6 Nations win last time out, but a repeat performance at the Stadio Flaminio will mean stopping imperious centre Brian O'Driscoll and his team, on a high after their 36-6 win over Scotland at Murrayfield.
However, the All Black legend insisted the threat is much greater than that posed by the Leinster man. The entire Irish backline and the danger of dwelling on the Wales win are serious worries for Kirwan as well.
"We need to be careful and not over-emphasise how we are going to stop O'Driscoll," he said.
"We have to tackle well and use our defensive strength.
"It is going to be very difficult to stop them. They are very well organised and tomorrow will be a very hard game for us.
"We have been working very hard this week, especially with the defence. The important thing is that we play rugby and enjoy time on the pitch."
But the New Zealander can also afford some small satisfaction at having achieved something significant since taking over the Italian job from compatriot Brad Johnstone last year.
"I have seen an improvement all across the board," he said. "With the clubs having improved that has helped the national team."
The infusion of confidence that the win over Wales has brought could prove either tonic or poison, and Kirwan is keen to ensure it does not end with a massive anti-climax against Ireland.
"I was very happy for the team and for Italy," he added.
"Now our challenge is to repeat last Saturday's perfomance and we won't change our approach.
"Our aim is still to have the best time possible and enjoy and improve our play."