SAINTS made it two victories in a week over neighbours Widnes with a comprehensive 11-try show.
Saints romped into a 26-0 interval lead to put the game to bed and then ran riot in the second half to ensure the Vikings stay bottom of the Stobart Super League.
Teenager Adam Swift, on his home debut, bagged a hat-trick and Anthony Laffranchi scored two tries for St Helens who had James Roby in dazzling form.
Saints, who survived a late rally to pip Widnes 40-38 in the Carnegie Challenge Cup last week, brought in Carl Forster for only his second appearance in place of Josh Perry.
But there was no Widnes fightback this time as Saints cruised to their fifth win in six matches under acting coaches Mike Rush and Keiron Cunningham.
Widnes made three changes in the backs with Joe Mellor, signed on loan from Wigan, Cameron Phelps and Stefan Marsh replacing Rhys Hanbury, Jack Owens and ex St Helens centre Chris Dean.
The Vikings went into the derby clash on the back of four defeats in a row since their last win against London in March and never looked like ending their miserable run.
They made a nervy start with two early handling mistakes and Saints almost went ahead from a Jonny Lomax kick before Shaun Magennis just failed to touch down.
The Vikings managed to hold out for 11 minutes before Roby, Lomax and Paul Wellens combined for Sia Soliola to force his way over to open up a 6-0 lead.
Skipper Wellens took an inside pass from Lance Hohaia with Roby again involved in the build-up to add a second try three minutes later.
Swift, who made his Saints debut in the cup win, earned the cheers of the fans with a sizzling clearance run from a Mellor kick.
Roby’s pass from dummy half sent Laffranchi crashing over from short range midway through the first half to extend the advantage to 16-0.
Widnes were on the back foot from the start and it was Roby again who was the provider for Laffranchi’s second try from an identical move.
The Vikings attack was as sloppy as their defence and Swift took Michael Shenton’s pass for his first try for the club just before the break.
It did not get any easier for Widnes early in the second half when Louis McCarthy-Scarsbrook outjumped the defence to collect Hohaia’s kick and stretch the lead to 32-0.
Sub Andrew Dixon brushed off Mellor to power over for his fifth try of the season and further expose the Vikings defensive frailties.
Shenton added the Saints seventh try courtesy of a smart back pass by Chris Flannery before Mark Flanagan touched down from Roby’s grubber kick.
It was Flanagan’s first touchdown for Saints since returning to England from Australian club Wests Tigers.
Paddy Flynn saved a try by chasing back to halt Francis Meli before Swift grabbed his second try with the youngster completing his hat-trick seven minutes from time.