Six Nations: Scott Johnson compares Scotland to an episode of 'CSI'

Coach wants his side to build on 'evidence' they have compiled so far in Six Nations

They are not short on entertainment value, this new-look Scotland. On the field, two games into the Six Nations championship, there has been the attacking verve that has yielded six tries. Off it, there have been such pearls of wisdom as Scott Johnson dropped into his team announcement at Murrayfield.

"It's like CSI," Scotland's bluff Aussie interim head coach said, pondering the trajectory of a team who bounced back from a 38-18 defeat against England at Twickenham with a 34-10 home win against Italy and who face Ireland in Edinburgh on Sunday.

"In week one all we left was fingerprints. In the second week we had eye witnesses to the event, so there was improvement. But in the third week we still want to be there when the police arrive.

"The fact is we've got to keep improving. We're not deluding ourselves. We need to get the tackle area right. We need to get the contact area right.

"The performance we produced against Italy won't be good enough to beat Ireland They may have made changes but they've had good success here and they're a world-class defensive unit, so we've got to take it up by another peg or two."

Ireland's head coach, Declan Kidney, has been obliged to make five changes to the starting XV beaten 12-6 by England the weekend before last. He has taken the bold step of replacing the injured Jonathan Sexton and Gordon D'Arcy with the uncapped Ulster duo Paddy Jackson and Luke Marshall in the pivotal 10-12 axis positions.

Jackson has been preferred at outside-half to the veteran Ronan O'Gara, who has been capped 127 times, Kidney saying: "It was a very difficult decision to leave Ronan out but I think Paddy deserves a go in this one." Tom Court replaces the suspended Cian Healy at loosehead prop, while Keith Earls and Donncha O'Callaghan come in for the injured winger Simon Zebo and lock Mike McCarthy.

Johnson has made just the one change, enforced by Euan Murray's refusal to play on Sundays on religious grounds. Geoff Cross fills the breach – a character as singular as Johnson himself, en erudite Borderer with a degree in medicine from the University of Edinburgh, whose alumni include Sir Arthur Conan Doyle, Alexander Graham Bell and Robert Louis Stevenson.

"I don't think I've ever coached a kid like him, but I thoroughly enjoy his company," Johnson said of the Edinburgh front rower. "He's right down my alley.

"I come in every morning not knowing what to expect and that's a pleasant surprise in this day and age. He's entertaining. As my old dad used to say: 'He's so heavenly that we're trying to find his earthly use'. I think we've found it as a tighthead prop."

The appreciation is mutual. Cross said of Johnson: "I enjoy working with him. The things he asks you to do are almost embarrassingly simple. But he asks you to do them extraordinarily well. He can be a bit of a philosopher but that's fine. I like that."