Newcastle Falcons' second-string sustained a narrow defeat in their final game of the A-League regular season on Monday night at Heywood Road.
Newcastle were already assured of second place in the Northern Conference with an away semi-final to follow (opponent TBC) and they led 12-7 at half-time.
Returning favourite Johnny Leota opened the scoring for Sale, albeit in the unfamiliar position of blind-side flanker as the Samoan sped between the posts.
Centre Tom Penny drew Newcastle level on 11 minutes with the first of four Falcons tries on a night when they helped themselves to a pair of bonus points.
Cumbrian hooker Jamie Blamire scored the first of his two tries on 23 minutes as the Falcons assumed a five-point interval lead, but the Jets hit back through centre Henry Vaka in the early stages of the second 40.
That left the teams tied at 12-12, Sale going seven clear five minutes later when Tomasi Tanumi crossed the whitewash for the home side.
Newcastle got to within two points when scrum-half Sam Stuart helped himself to the visitors' third try, but Ciaran Booth's bonus-point try wrapped things up for Sale.
Newcastle grabbed a pair of bonus points late on courtesy of Blamire's second try, but it was the home side who emerged victorious from the end-of-season dead rubber.
Academy manager and first team skills coach Mark Laycock said: "We're very frustrated and disappointed to only come away with two bonus points.
"We were 12-7 up at half-time despite missing a number of chances, and this result isn't what we have been working for.
"Our junior academy players and the guest players who came in from local clubs and universities got some valuable game time and it was good in that sense, but we lacked composure in attack and made basic defensive errors.
"We have an away semi-final next Monday night, and will need to significantly improve on this performance if we are to proceed into the final."
Newcastle Falcons A: 15 Cameron Cowell, 14 Adam Radwan, 13 Tom Penny, 12 Charlie Wilson, 11 Zach Kibirige, 10 Joel Matavesi, 9 Sam Stuart; 1 Adam Brocklebank, 2 Jamie Blamire, 3 Jake Ilnicki, 4 Andrew Davidson, 5 Morgan Eames (Doncaster Knights), 6 Jack Payne, 7 Matt Salway (Northumbria University), 8 Max Davies.
Replacements: 16 Alistair Blackett (Junior Academy), 17 Sami Mavinga, 18 Trevor Davison, 19 Will Montgomery (Junior Academy), 20 Tom Marshall (Junior Academy), 21 Craig Willis, 22 Dan Kelly (Leeds Beckett), 23 Aedan Moloney (Northumbria University).
Sale Jets: 15 Tomasi Tanumi, 14 Taraisi Wara, 13 Billy Wara, 12 Henry Vaka, 11 Chris Owen, 10 James Robbins, 9 Matt Sturgess; 1 Jake Pope, 2 Curtis Langdon, 3 Brandon Palmer, 4 Matt Postlethwaite (captain), 5 Charlie Pozniak, 6 Johnny Leota, 7 Teddy Leatherbarrow, 8 Ciaran Booth.
Replacements: 16 Nic Dolly, 17 Monty Weatherby, 18 Paul McGookin, 19 Matt Garrod, 20 Connor James, 21 Connor Adams, 22 Mike Barlow, 23 Wes Hamilton.
Referee: John Meredith