St Helens made it four wins out of four thanks to a supercharged second-half showing to move clear at the top of the table and leave Hull KR still seeking their first Super League victory of the season.
Rovers held Saints 12-12 at the break, but conceded five touchdowns after the interval, with Adam Swift turning in a man-of-the-match display.
Swift led the way with two tries for the hosts and also created another for captain Jon Wilkin.
Saints handed Samoan Mose Masoe his debut off the bench, and the 24-year-old former Penrith Panthers prop, who had been sidelined following ankle surgery after being injured during the World Cup, played 30 minutes in two spells after his long lay-off.
Gary Wheeler was also back after missing last week’s triumph over Salford with a dead leg.
Hull KR welcomed back forwards Michael Weyman and Justin Poore from suspension and Jamie Langley from concussion, but Jonny Walker was out with a serious knee injury.
Rovers would have grabbed an early lead had Ben Cockayne been able to take a pass from Greg Eden after a mistake by Alex Walmsley, which earned an angry rebuke from Luke Walsh.
But then Walsh spilled the ball, only for Rovers full-back Eden to throw a wild pass from the scrum which was snapped up by Swift to race over after six minutes.
Walsh tagged on the conversion and his well-judged high kick to the corner almost brought another score for Tommy Makinson, who just failed to touch down.
Rovers were under the cosh and they conceded a second try after Swift sent Jonny Lomax away and the full-back dummied Eden to make it 12-0, with Walsh booting the conversion.
Sandercock’s men hit back, though, with Poore and Eden going close before Lance Hohaia had a ‘try’ correctly disallowed by referee Tim Roby.
Then it was Rovers’ turn to be disappointed when Liam Salter’s effort was ruled out after a smart tap-back by Craig Hall from Kris Keating’s kick.
It was 30 minutes before the first penalty came and, although Rovers failed to find touch, they did cross for their opening try from Kevin Larroyer following smart play by James Green. Burns added a difficult conversion.
Rovers deservedly drew level 12-12 by the break with Jordan Turner moving out of the Saints’ line too fast for Cockayne and he sent Eden over for a converted try.
Saints regained the lead eight minutes after the restart with Alex Walmsley crashing over to make it 18-12.
Swift then bagged his second try, created by Wilkin and Lomax.
Walsh set up two tries in three minutes for Sol Soliola and Makinson with teasing kicks to stretch the lead to 32-12.
Wheeler blew another chance with his second handling error before Masoe returned for his second spell 12 minutes from time – with Swift jumping high to put Wilkin over from another Walsh kick.
The impressive Hodgson caught Saints napping to dart over from a quickly-taken tap penalty to make the scoreline more respectable.
Rovers finished with 12 men with Burns sin-binned for obstruction on Wilkin before Paul Wellens had a ‘try’ disallowed.
St Helens: Lomax, Makinson, Turner, Wheeler, Swift, Hohaia, Walsh, Walmsley, Roby, Amor, Wilkin, Manu, Jones. Substitutes: Masoe, McCarthy-Scarsbrook, Soliola, Wellens.
Hull K R: Eden, Cockayne, Salter, Welham, Hall, Burns, Keating, Poore, J. Hodgson, Weyman, Larroyer, Langley, Horne. Substitutes: A. Walker, Cox, Lovegrove, Green.
Referee: T Roby (RFL).