Saracens completed a memorable European and domestic double after retaining the Premiership title by beating Exeter 37-34 at Twickenham.
The teams shared 10 tries during unquestionably the greatest Premiership final in its 16-year history.
Exeter led after just 28 seconds when scrum-half Nic White claimed the quickest Premiership final touchdown, but Saracens ultimately prevailed.
The Chiefs led by 11 points after an hour, yet Saracens produced a stellar comeback.
Wings Liam Williams and Sean Maitland touched down, following earlier tries from hooker Jamie George and scrum-half Ben Spencer, before George added a second and Farrell kicked 12 points.
White, flanker Dave Ewers, lock Jonny Hill, centre Henry Slade and substitute Sam Hill crossed for Exeter, and Joe Simmonds added three conversions and a penalty, but the Chiefs once again experienced Twickenham heartbreak.
It was the third time in four seasons for the 2017 champions to lose a final – all against Saracens – as Farrell and company followed up European title success three weeks ago with another trophy.
And it meant a second double in four years, emulating Leicester as only the second English club to achieve such a feat.
Both teams were unchanged following their play-off victories last weekend, with Saracens captain Brad Barritt overcoming a hamstring injury that forced him off against Gloucester to start.
And the final began in remarkable fashion, with 12 points being scored inside the opening five minutes.
Exeter kicked off, but Saracens and England lock George Kruis fumbled possession, giving the Chiefs the chance to attack on front-foot ball and White crossed from close range for a try that Simmonds converted.
But Saracens responded, launching an initial attack that ended when Slade deliberately knocked on a pass from full-back Alex Goode to Maitland, and was sin-binned by referee Wayne Barnes as a result.
Slade had barely left the pitch before Saracens drove a lineout from the resulting penalty, and George crashed over.
Farrell missed the conversion, but he landed a 35-metre penalty shortly afterwards and Saracens led 8-7 following a breathless start.
Saracens then extended their lead following a Billy Vunipola scrum charge that spread Exeter's defence, and Spencer touched down to open up a 13-7 advantage.
Farrell again could not add the extras, and Exeter replied following another frantic passage of play that started with them laying siege to Saracens' line.
Saracens were reduced to frantic defending, and flanker Maro Itoje, who was sin-binned during the Champions Cup final victory over Leinster, again saw yellow, and Exeter did not require a second invitation to pounce.
A man down, Saracens could not hold out under sustained pressure, and Ewers claimed Exeter's second try before Smmonds' conversion gave them a one-point advantage.
And the Chiefs moved further ahead nine minutes before the break when Slade and his England colleague Jack Nowell linked superbly in midfield, before Hill touched down.
Simmonds' conversion glanced off the post, then Farrell booted a 40-metre penalty that cut the deficit to three points, but Simmonds responded and Exeter trooped off 22-16 ahead at the break.
Barritt, though, did not return for the second period, being replaced by Nick Tompkins, before Spencer went off for a head injury assessment as Saracens suffered a disruptive opening.
Saracens dominated much of the third quarter, but Exeter continued to hassle and chase them, making life distinctly uncomfortable for their opponents.
And such in-the-face-pressure was rewarded through a fourth try, with Slade the beneficiary following brilliant work by replacement lock Sam Skinner.
But Saracens responded again and Williams struck after a Farrell kick, with the fly-half's conversion making it 27-23.
Maitland then crossed 12 minutes from time, with Farrell converting, and although the fly-half missed a later penalty chance, George's second touchdown sealed the deal and Saracens were home, despite Hill's late effort that Simmonds converted.
