Farrell believes Ireland lost their defensive "appetite", leaking three tries in a lacklustre opening half-hour at Murrayfield that handed Scotland victory.

Now the British and Irish Lions assistant coach has demanded his players rediscover their defensive relish ahead of facing Italy in Rome on Saturday.

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

"So our mood was affected, our appetite was affected a little bit, and we got it back in the second half.

"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.

"Our mood was completely different in the first half compared to what it was in the second half and I think we let things a little bit affect us and we shouldn't do that defensively. We should love defending."

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

Now Ireland know they must win all four remaining Six Nations matches to stand any chance of contesting this year's title, starting by facing Conor O'Shea's Italy this weekend.

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.

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

For the feisty former dual-code international, this proved an anecdote too far - but at least one he has impressed on his players.

"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.

Former Ireland full-back 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," Farrell said.

"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."