The pounds 80,000 signing from Widnes moved to scrum-half as Goulding began his latest suspension and it says everything about his performance that Goulding was not missed as Long scored two tries, made another and kicked three goals for good measure.
Salford were confronted in the opening minutes by a St Helens side playing some of its most decisive rugby of the whole season.
A remarkable pass out of the tackle by Derek McVey sent Alan Hunte sprinting 70 yards for the first try, raising the question of how Saints can be so willing to see him leave before next season.
Equally good handling by Apollo Perelini and Hunte sent Long in for their second try and Long's kick brought up double figures with the promise of plenty more to come.
Salford's cause was not helped by conceding seven penalties in a row and when Lokeni Favelio was sin-binned for interfering at the play the ball, they looked increasingly up against it.
But despite being short-handed, Salford clawed their way back into the game spiritedly, using the ball just as well as Saints had done earlier in the half for Peter Edwards and David Hulme to give Darren Rogers the chance to score in the corner.
Steve Blakeley landed the goal from the touch line - his 100th of the season - and Salford would have been level at half-time had it not been for his missing two easier efforts.
But with Long calling the shots, Saints again started like the proverbial house on fire. His break setting up Anthony Stewart to show real pace in going half the length of the field for his first try for the club.
Long then started and finished a move involving Karle Hammond, Perelini and Ian Pickavance for his own second try.
Salford threatened a comeback, especially when Saints had Hammond sent to the sin-bin, but the home side wrapped it up with a close-range try from Keiron Cunningham.
Evan after Gary Broadbent was sent off for a high tackle on Danny Arnold, Salford managed a reply in the last minute, Scott Naylor chasing Mark Lee's kick, but a season which had delivered more than it promised for them had gone on a little too long.
St Helens: Arnold; Stewart, Hunte, Newlove, Sullivan; Hammond, Long; Leathem, Cunningham; Pickavance, McVey, Perelini, Joynt. Substitutes used: Booth, Matautia, Morley, Anderson.
Salford: Broadbent; Sini, Naylor, McAvoy, Rogers; Blakeley, Lee; Platt, Edwards, Savelio, Faimalo, Cartwright, Forber. Substitutes used: Martin, Hulme, Bradbury, Burgess.
Referee: S Cummings (Widnes).Reuse content