Castleford were made to work for the two points by a young St Helens side as the Tigers ran-out 30-10 winners at the Jungle.
St Helens coach Kristian Woolf handed out seven debuts to academy products – Jumah Sambou, Daniel Hill, Daniel Moss, Lewis Baxter, Taylor Pemberton, George Delaney and McKenzie Buckley.
Meanwhile, Castleford forward Nathan Massey made his 300th career appearance.
The Tigers couldn’t have dreamt for a better start as Jason Qareqare scored inside the first minute from a 90-metre effort.
Derrell Olpherts extended Castleford’s lead in the 25th minute before Jake Trueman went over to give Lee Radford’s side a comfortable 14-0 lead at the break.
HT: Castleford Tigers 14-0 St Helens
Olpherts got his second for Castleford in the 50th minute to put them in a healthy lead.
Debutant Sambou scored Saints’ first try of the game on the hour mark with an acrobatic finish in the corner.
Three minutes later, in-form forward James Bell wrestled his way over from close range. Debutant Shay Martyn converted to make the score 18-10.
But Joe Westerman put the game out of reach for Saints in the 66th minute, with Paul McShane converting.
Mahe Fonua added another late on for the Tigers to help them secure a 30-10 win.
Castleford have now won four games on the spin. Meanwhile, champions St Helens have lost their second game of the season after losing in the south of France against Toulouse earlier on in the year.
FT: Castleford Tigers 30-10 St Helens
Castleford: Clare; Olpherts, Mamo, Fonua, Qareqare; Trueman, O’Brien; Watts, McShane, Griffin, Edwards, Lawler, Westerman. Subs: Milner, Massey, Smith, Martin.
Tries: Qareqare, Olpherts (2), Trueman, Westerman, Fonua Goals: McShane 3
St Helens: Bennison; Sambou, Simm, Hill, Martyn; Davies, Moss; Amor, Lussick, Norman, Royle, Bell, Wingfield. Subs: Baxter, Pemberton, Delaney, Buckley.
Tries: Sambou, Bell Goals: Martyn 1