Despite an early yellow card for Sam Prendergast on his first Irish start, after giving away 13 penalties in both prior autumn games, Farrell thought this time around that Ireland's discipline helped them to victory.
"I thought our discipline was pretty good in general and it certainly added to the reason why, if you look at the story of the game and you fast forward it, I thought territory-wise and dominance-wise, yes, a couple of execution bits could have been better, but I thought our discipline added to our stronghold on the game."
Playing four games this autumn rather than their customary three, Ireland will face Australia next week in a Test that will mark the Irish Rugby Football Union's 150th anniversary. Farrell wants to see his side step up again to finish the block on a high.
"As you would expect me to say, the best is yet to come. It has to be," he said.
"We're playing against a buoyant Australian side that play some really nice rugby, but the week's going to be a special one for us.
"It's going to be a marked game for the 150th anniversary. We talk a lot about the shirt and what it means for us so it's going to be a big week coming up."