St Helens have sealed a spot in the Super League playoff semi-final after crushing Castleford Tigers 41-0 this evening.

Following a cagey opening spell, James Roby scored two tries in the space of seven minutes to give the hosts a 12-0 lead, before Jordan Turner kicked a drop goal on the stroke of half time.

St Helens continued to dominate after the break, with Turner diving under the posts following a quick break at the start of the second half.

Adam Swift extended their advantage with just over 20 minutes to play, gathering a loose ball before running back 60 metres for the fourth try of the night.

As they continued to grow in confidence, Saints ran the score up further, crossing the tryline three more times before full time to emphatically book their spot in their last four.

Castleford will get another chance to reach the semi-finals next weekend in the preliminary semis, facing a winner from the elimination playoffs.