|Ospreys (21) 43
|Tries: Lake 4, Thomas, Morris Cons: Williams 4, Walsh Pen: Walsh
|Benetton (24) 34
|Tries: Ratave 2, Negri, Odogwu Cons: Umaga 4 Pens: Umaga 2
Dewi Lake starred as Ospreys opened their Challenge Cup campaign with a bonus-point victory over Benetton.
The hooker crossed four times as momentum swung back and forth in a thrilling 10 try encounter in Swansea.
Lake was one of a handful of returning Wales internationals as Ospreys avenged last weekend's league defeat.
Onisi Ratave scored twice on the wing for the visitors, but it was ultimately an evening for the forwards and notably the Ospreys driving maul.
Ospreys had gone down 18-13 in Treviso last weekend, but welcomed back Lake, Jac Morgan and Adam Beard to bolster the pack, while George North started for the first time since confirming his move to French club Provence at the end of the season.
Ospreys started brightly with Luke Morgan's line break sparking the attack for the opening try.
Lake was involved throughout the patient build-up before finishing off from close range to begin his try-scoring rout.
Benetton hit straight back, as they did all evening, Ratave taking advantage of a simple two on one down his right wing.
Momentum then swung back the way of the hosts, the returning Morgan carrying hard alongside Lake before releasing Gareth Thomas who shrugged off the tackle before outstretching his arm over the try line.
Ratave then popped up on the opposite wing to bring the scores back level, the Fijian making a memorable first appearance of the season with a second score.
Ospreys re-took the lead with a trademark driving maul, Lake finding his target at the lineout before latching onto the back of the pack and touching down for his second.
Benetton's inevitable response came through Paolo Odogwu whose meandering run released Sebastian Negri who did well to ride the tackle and touch down in the corner.
Morgan conceded a penalty just before the break which allowed Jacob Umaga to kick the visitors to a slim 24-21 advantage after an entertaining six try half.Ospreys skipper Morgan Morris scored the game's decisive try
Ospreys struck first in the second half and there was to be no stopping the power of player of the match Lake who recycled after more patient play from the forwards.
But true to fashion, Benetton came straight back, Odogwu showing his finishing prowess after finding some space out wide.
Ospreys put themselves back ahead after Owen Williams' great touch finder set up a five metre driving lineout which again provided the carriage to get Lake over the line.
Williams and Umaga traded long-range attempts at goal as the tries momentarily dried up, but the turning point came when Benetton were reduced to 14 men.
Replacement loose-head Mirco Spagnolo was shown a yellow card for being off his feet while competing at the ruck, and backing their lineout, Ospreys kicked for touch to set up Morgan Morris' final try of the game.
Benetton were then dealt a further blow and denied a deserved losing bonus-point when Jack Walsh kicked a penalty at the death.
Ospreys: Iestyn Hopkins; Luke Morgan, George North, Owen Watkin, Keelan Giles; Owen Williams, Reuben Morgan-Williams; Gareth Thomas, Dewi Lake, Tom Botha, James Fender, Adam Beard, Rhys Davies, Jac Morgan, Morgan Morris (capt).
Replacements: Sam Parry, Nicky Smith, Ben Warren, Harri Deaves, Tristan Davies, Luke Davies, Jack Walsh, Mat Protheroe.
Benetton: Edoardo Padovani; Paolo Odogwu, Ignacio Brex, Malakai Fekitoa, Onisi Ratave; Jacob Umaga, Andy Uren; Thomas Gallo, Gianmarco Lucchesi, Giosue Zilocchi, Niccolo Cannone, Federico Ruzza, Sebastian Negri, Michele Lamaro (capt), Lorenzo Cannone.
Replacements: Bautista Bernasconi, Mirco Spagnolo, Filippo Alongi, Gideon Koegelenberg, Riccardo Favretto, Toa Halafihi, Sam Hidalgo-Clyne, Leonardo Marin.
Referee: Ludovic Cayre (Fra)
Assistant referees: Baptiste Nuchy & Pierre Bru (Fra)
TMO: Patrick Dellac (Fra)