Northampton had to work hard to post a bonus-point LV= Cup win over the Ospreys at the Brewery Field, Bridgend.
The hosts led 19-12 at the break thanks to man-of-the-match Matthew Morgan's boot and a Sonny Parker try.
But the Saints, with returning World Cup players such as Dylan Hartley, Courtney Lawes, Soane Tonga'uiha, Ben Foden, Vasily Artemyev and Chris Ashton in their ranks, proved too strong.
Hartley went over twice with Artemyev and Callum Clark also touching down.
Ryan Lamb kicked three conversions and a penalty and his replacement, Stephen Myler's late shot denied the Ospreys a losing bonus point.
Ospreys: R Jones; Prydie, John, Parker, E Walker; Morgan, Habberfield, Griffiths, Baldwin, Jarvis, Smith, Evans, King, Lewis, Allan.
Replacements: Phillips for R. Jones (70), Price for John (63), Grabham for Habberfield (60), D. Jones for Griffiths (50), M. Davies for Baldwin (60), Rees for Jarvis (50), Kelly for Evans (77), O'Toole for Lewis (60).
Northampton: Foden; Ashton, Armstrong, Downey, Artemyev; Lamb, Dickson; Tonga'uiha, Hartley, Doran-Jones, Lawes, Sorenson, Clark, Wood, Wilson.
Replacements: Clarke for Downey (59), Myler for Lamb (63), Roberts for Dickson (64), Haywood for Hartley (62), Mercey for Doran-Jones (59), Manoa for Lawes (62), Dowson for Wilson (59).
Not Used: A Waller.
Ref: Neil Hennessy (Wales).