Second-placed Hull KR lost to Harlequins meaning that Saints now have a five-point advantage over their nearest rivals.
Long’s forty-twenty gave Saints the field position for Cunningham to score before Jon Wilkin touched down, Long converting the latter for a 20-6 half-time lead.
The Tigers got onto the scoresheet for a second time after the restart, Dixon touching down after Francis Meli failed to collect a high kick.
Saints, however, hit back when Long was able to create a try out of nothing and convert to make the score 26-10, before quick tries from Lomax and Eastmond, who converted both.
Clough got in on the act with a try in the final ten minutes, Eastmond converting both that and his own try just moments later, bringing up the fifty for Saints.