Six Nations 2017: Ireland must regain defensive 'appetite' - Andy Farrell

Sean O'Brien makes ground for Ireland at the expense of Stuart Hogg

Ireland must regain their "appetite" for defence if they are to rescue their Six Nations hopes against Italy this weekend, Andy Farrell says.

The defence coach watched Ireland leak three tries in a lacklustre opening half hour as they lost 27-22 to Scotland at Murrayfield on Saturday.

"Every single time we get an opportunity to defend, we should love it, and we didn't," Farrell said.

"Our mood was completely different in the first half compared to the second."

The British and Irish Lions assistant coach added: "We'll work on the reasons why. I'm more concerned about the mood at the time, of our lack of want to get back in the line and enjoy our defence."

Ireland turned a 21-5 deficit into a 22-21 second-half lead in Scotland, thanks to tries from Keith Earls, Iain Henderson and Paddy Jackson.

But head coach Joe Schmidt's men could not hold on, with Greig Laidlaw slotting two decisive late penalties.

Ireland know they must win all four remaining Six Nations matches to stand any chance of contesting this year's title.

Farrell revealed the greatest frustration from his weekend, however, was hearing Scotland boss Vern Cotter suggest Ireland had altered their defensive system mid-match to combat their sluggishness.

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The former England coach insisted Ireland did not alter their technical approach one iota - instead saying a sizeable attitude shift shored up their rearguard action.

"I think the upsetting thing for myself after the game was that Vern Cotter came up to me - and Scotland, all credit to them, I thought they played really well, especially in the first half - but he said, 'Jeez, you changed your defence in the second half, didn't you?'.

"And we didn't. We didn't. So now you can understand why I'm talking about the mood."

Wales ground past Italy 33-7 in Rome last weekend, but Ireland remain wary of the Azzurri, especially after their 20-18 win over South Africa in November.

Italy coach Conor O'Shea is fighting to engender a new depth of spirit, and Farrell anticipates a tough encounter.

"We need to enjoy our defence this weekend against Italy, we need to get the ball back because if we don't, the Italians are going to be hard work for us," said Farrell.

"It's a tough old match over there and we've seen plenty of games where teams have come unstuck so you have to be at your best in this championship against absolutely everyone.

"We know what the Italians can do, we know what they've done against South Africa and we know that they believe that if they get a sniff... so we've got to apply ourselves on the Italians and we need to get that appetite consistently higher this weekend."