Fifth-placed Hartpury took the lead on 24 minutes when Sebastien Rodwell went over and Gareth Knox converted.
Third-placed Raiders responded well, though, and, after Matt McLean kicked a penalty, they touched down twice in the space of two minutes through Jack Maslen’s excellent run from his own half and Kiba Richards.
McLean kicked one of the conversions to give Raiders a 15-7 half-time lead.
Man-of-the-match Maslen went over for his second try on 54 minutes, with McLean again converting, before Worthing secured their four-try bonus point five minutes later.
A quick passing move between Ben Dudley, McLean and Jamie Redmayne saw Redmayne go over, with McLean again adding the extras.
Hartpury scored a late converted penalty try as Raiders comfortably held on for the win.
Raiders coach Kieron Dawson said: “We’ve played the two teams below us in our last two games and beaten them both, so have made it a three horse race for the title now.
“It’s a huge game at Richmond next week now and it would be great to see as many Raiders fans as possible there.”