Crosfields had only previously been beaten once in nine league outings and came into their home game top of the table, but slipped down to third with the loss to a Knights team in fourth position.
After return to their best form in a 44-16 win over Dewsbury Moor Maroons the previous week, Normanton kept the good work going as they made the early running and went 12-0 up with tries by Luke Camplin and Connor Wilson.
They never looked back, despite the Soap three times recovering to within six points in a tit-for-tat affair.
The Knights, having added touchdowns by Jacob Crossland and Ashley Haynes, sealed victory with an Alex Barker effort, with Joe Abson landing his second conversion after taking over the kicking duties from three-goal man Joe Crossland.
Crosfields’ frustrations showed as they had Matt Barber sin-binned on 72 minutes for striking.
They had kept in touch in the game, however, through tries by John Whittaker, Oliver Livett, Alex Clutterbuck and Jacob Chamberlain, three of which Brad Stanway improved.
Normanton take a break from the league this weekend before returning to action on Saturday, June 4, at home to Hunslet Warriors (kick-off 2.30pm).