Wales fly-half Dan Biggar kicked 14 points as the Ospreys ground out a 24-19 victory over Treviso in Italy.
Biggar's haul was joined with tries from Scott Baldwin and Ben John to give the Welsh region the win in a scrappy encounter.
Italy international Simone Favaro scored Treviso's only try with fly-half Alberto Di Bernardo adding 14 points from the boot as the hosts secured a losing bonus point.
Lions heroes Adam Jones, Richard Hibbard and Ian Evans all started on the bench for the Ospreys and it was the Italians who got the first points of the game as Di Bernardo converted an penalty after Andrew Bishop was sent to the sin-bin.
But Biggar levelled the scores three minutes later, over-taking Ronan O'Gara as the league's second top scorer of all time, with a 13th minute penalty.
The 2011/12 champions turned up the heat and their patient approach at the line-out paid off as Baldwin bundled his way over the whitewash, with Biggar converting, to put the Welsh side ahead after Leonardo Ghiraldini was yellow carded for pulling down a maul.
Tom Smith was penalised for being offside just after the half hour and Di Bernardo, who struck the post from a similar position only minutes earlier, kicked the resulting penalty to reduce Treviso's deficit to four points.
The fly-half notched another three points on the brink of half-time after Tito Tebaldi was harshly punished by referee Neil Paterson for not releasing to leave the Italians trailing by a point at the interval.
Treviso regained the lead six minutes into the second period with a fourth penalty from Di Bernardo before Biggar's drop-goal restored the Ospreys' slender one-point lead.
Steve Tandy introduced his Welsh heavyweights from the bench and they soon scored their second try as John rose above Luke McLean to gather Tebaldi's kick to put the Ospreys six points ahead.
Biggar gave the Ospreys some breathing space as he slotted over a second drop-goal but Treviso set up a tense finish as Favaro crossed over from a driving maul, with Di Bernardo adding the extras.
The visitors' front-row proved pivotal in the final stages as they decimated Treviso in the scrum to allow Biggar to kick another three points to give the Ospreys a five point lead with eight minutes left on the clock.
Treviso refused to lie down and were camped on the Ospreys' try-line for the final five minutes but the Welsh side held on to secure the victory.
Con: Di Bernardo
Pens: Di Bernardo 4
Tries: Baldwin, John
Pens: Biggar 2
Drop Goals: Biggar 2
Treviso: 15 Brendan Williams, 14 Ludovico Nitoglia, 13 Luca Morisi, 12 Alberto Sgarbi, 11 Luke McLean, 10 Alberto Di Bernardo, 9 Edoardo Gori, 8 Robert Barbieri, 7 Alessandro Zanni, 6 Manoa Vosawai, 5 Valerio BernabÃ², 4 Antonio Pavanello (capt), 3 Alberto De Marchi, 2 Leonardo Ghiraldini, 1 Michele Rizzo.
Replacements: 16 Giovanni Maistri, 17 Ignacio Fernandez-Rouyet, 18 Lorenzo Cittadini, 19 Dean Budd, 20 Christian Loamanu, 21 Simone Favaro, 22 Fabio Semenzato, 23 Tobias Botes.
Ospreys: 15 Richard Fussell, 14 Ben John, 13 Andrew Bishop, 12 Ashley Beck, 11 Eli Walker, 10 Dan Biggar, 9 Tito Tebaldi, 8 Joe Bearman, 7 Sam Lewis, 6 Tom Smith, 5 James King, 4 Ryan Jones (capt), 3 Joe Rees, 2 Scott Baldwin, 1 Ryan Bevington.
Replacements: 16 Richard Hibbard, 17 Duncan Jones, 18 Adam Jones, 19 Ian Evans, 20 Morgan Allen, 21 Tom Grabham, 22 Matthew Morgan, 23 Jeff Hassler.
Referee: Neil Paterson (SRU)