|Zebre (8) 14|
|Cons Garcia Pens 3|
|Ospreys (6) 15|
|Pens Davies 5|
Replacement fly-half Sam Davies kicked five penalties in Ospreys' hard-fought win against Zebre that kept the Welsh region unbeaten in the Pro12.
Wales stand-off Dan Biggar left the field early on on after a collision.
And while ex-Wales Under-20 cap Davies missed four shots at goal, his 71st-minute kick edged the contest.
Giulio Bisegni's superb try as Biggar lay on the ground was the game's highlight, while Gonzalo Garcia kicked nine Zebre points.
The hosts may have felt hard done-by after scoring the only try. But after seeing off Ulster in the previous round, the Italian side at least earned a losing bonus point.
For the visitors, there was a measure of revenge having suffered a 30-27 defeat in Parma in May.
Ospreys prospects looked damaged when Biggar departed after six minutes following a mid-air collision with home wing Leonardo Sarto.
But Biggar's fellow former Wales Under-20 cap Davies impressed with his assured efforts amid a scrappy opening period in which Zebre came out on top.
The hosts capitalised on the incident in which Biggar's game ended with a spectacular counter-attack that ended with centre Bisegni going over.
Davies and Garcia exchanged penalties amid the arm-wrestle that occupied the rival packs.
And Davies ensured his side went into the break only two points behind with his second success.
Garcia kicked his second penalty and Ospreys responded by introducing star performers Rhys Webb and skipper Alun Wyn Jones to the fray.
Ospreys' best passage of play was inspired by captain Jones' powerful burst that prompted wing Giulio Toniolatti to kill possession illegally, earning him 10 minutes in the sin bin.
Davies was unable to punish that offence, but put Ospreys ahead for the first time in the 66th minute with his fourth penalty.
Garcia restored the hosts' advantage but, as the tension mounted, Davies was proved equal to the call.
Zebre: Hendrik Daniller; Giulio Toniolatti, Giulio Bisegni, Gonzalo Garcia, Leonardo Sarto; Luciano Orquera, Guglielmo Palazzani; Matias Aguero, Andrea Manici, Dario Chistolini, George Biagi, Marco Bortolami (capt), Mauro Bergamasco, Samuela Vunisa, Filippo Cristiano.
Replacements: Oliviero Fabiani, Andrea Lovotti, Luciano Leibson, Quintin Geldenhuys, Valerio Bernabò, Alberto Chillon, Kelly Haimona, Mirco Bergamasco.
Ospreys: Dan Evans; Jeff Hassler, Jonathan Spratt (capt), Josh Matavesi, Hanno Dirksen; Dan Biggar, Martin Roberts; Nicky Smith, Scott Baldwin, Dmitri Arhip, Lloyd Peers, Rynier Bernardo, Joe Bearman, Morgan Allen, James King.
Replacements: Sam Parry, Duncan Jones, Cai Griffiths, Alun Wyn Jones, Sam Lewis, Rhys Webb, Sam Davies, Andrew Bishop.
Referee: Lloyd Linton (Scotland)
Assistant referees: Elia Rizzo, Carlo Damasco (Italy)
Citing commissioner: Stefano Roscini (Italy)