Newport Gwent Dragons sent Magners League title-chasers the Ospreys packing in an exhilarating encounter at Rodney Parade.
The hosts scored four tries for a bonus point as they completed a season's double for the first time over the star-studded Swansea-based side.
Aled Brew, Ashley Smith and Wayne Evans crossed for the hosts as they built a 32-11 lead.
Ryan Jones, Tommy Bowe and Nikki Walker hit back for the visitors.
The rest of the points fell to Dragons kickers James Tovey and Matthew Jones, with Dan Biggar and James Hook responding for the Ospreys.
Biggar opened the scoring for the visitors with a penalty after home lock Adam Jones was penalised at an early ruck.
But the Dragons conjured an impressive response, seizing on a turnover to take the lead.
Scrum-half Wayne Evans launched the counter-attack and skipper Smith sent the ball wide to Faletau.
The number eight sent Hook and Lee Byrne the wrong way with a half-dummy to wing Brew, then found Smith in support inside and the centre went over and Tovey converted.
Under the guidance of new coach Darren Edwards, the Dragons were clearly intent on attacking at every opportunity while the Ospreys were content to kick for territory.
That paid off for the visitors as the pressure allowed lock Ryan Jones to score at the corner after Hook gave him the space to squeeze over.
Hook and Bigger missed penalties, as did Dragons fly-half Tovey.
But the biggest missed chance of the opening period fell to Brew. Tovey's near perfect grubber kick sent the wing on a clear chase, but he over-ran the ball and knocked it into touch with the line begging.
Tovey added two penalties and Biggar replied with a single effort to give the Dragons an 11-8 half-time lead.
Three minutes after the break scrum-half Evans touched down after a multi-phase attack that found the Ospreys wanting, Matthew Jones adding the conversion.
After his unfortunate moment in the opening period, Brew found himself on the receiving end of some good luck at Bowe's expense.
The Irish international won the chip-and-chase race, but he tried to hack the ball out of play, missed by a wide margin and Brew was on hand to pounce and score for Tovey to convert.
Brew then scored the Dragons' bonus-point try, again with some good fortune as his counter-attack began after his kick ahead rebounded off a defender.
The wing raced away, baffling Hook on a 45-metre dash to the line for Jones to convert.
However, the momentum swung dramatically to the Ospreys, as Hook's pass gave Bowe the chance to cut inside and finish in style for Hook to convert.
Hook had moved to fly-half when Biggar departed amid a glut of Ospreys replacements after 50 minutes and his influence was obvious in the visitors' resurgence.
After creating Bowe's 59th-minute try, two minutes later his inch-perfect cross-kick allowed Nikki Walker to run in unopposed on the other flank, Hook again adding the conversion.
The Perpignan-bound Wales and British and Irish Lions star added a penalty after 65 minutes to leave the Ospreys four points adrift.
But that is how it stayed as the Dragons celebrated Darren Edwards' first game in permanent charge with a well-deserved, hard-fought win in which Faletau's outstanding display earned him Scrum V pundit Jonathan Davies' man-of-the-match award.
"Faletau was immense," said Davies as he tipped the Tongan-born number eight for a Wales starting berth against the Barbarians on Saturday, 4 June at the Millennium Stadium.
Newport-Gwent Dragons: Harries; Hughes, Riley, Smith, A Brew; Tovey, W Evans; Price, Burns, Castle, Coombs, A Jones, Lydiate, Faletau, G Thomas.
Replacements: M Jones for Harries (10), Bearman for Lydiate, (60), Gustafson for Price (temp 27-34), S Jones for Burns (69), Way for Castle, (73), L Evans for Coombs (63)
Not Used: Pewtner, J Evans.
Ospreys: Byrne; Bowe, Bishop, Hook, Walker; Biggar, Webb; James, Bennett, A Jones, R Jones, A W Jones, Smith, Collins, Holah.
Replacements: Bevington for James (55), Isaacs for Webb (55), Hibbard for Bennett (48), Griffiths for A. Jones (55), Parker for Collins (55), Tipuric for Holah (55), Gough for R Jones (50), Fussell for Bishop (60).
Ref: N Owens (WRU).