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It's a notion that's been building for moths, but now it's official: Farrell is a man.
And as he ascends in both club and national team colours, the 22-year-old continues to go lead his line-ups with a candour that's far beyond his years, unafraid of any test, it seems.
You could make note of this "lesson" at any juncture this season, but a 2013-14 Premiership final at Twickenham just a week after losing in a Heineken Cup final seems an apt time to praise the young gun for his mental fortitude.
It will help that ex-international father Andy is there to guide him through these waters that have been the downfall of many an up-and-coming star, but the work done on Saturday's turf was all down to the fly-half himself.
Farrell was involved in just about every aspect of play, and if the Northampton pack targeted him as a potential weak spot in the Saracens defence, they could have chosen better.
By halftime, Farrell had missed just one tackle, slotting two of his three attempted penalties, and only Schalk Brits had beaten more defenders within his side's ranks.
His probing with the boot was expert level, and as ever, Farrell was ever willing to punish the opponent for showing him the slightest of gaps, forcing breaks in a straight and to-the-point manner as he continues to excel, irrespective of his age or the occasion surrounding him.
It may not have been enough after Charlie Hodgson came on for Farrell with 20 minutes of normal time left, but the youngster's reputation is by no means harmed as a result.