Wigan Warriors confirmed a home playoff and left Castleford’s top five hopes hanging by a thread after a 26-8 win at the DW Stadium.
Castleford drew first blood after 10 minutes as Jamie Ellis scored a penalty in front of the posts.
But it was Wigan who scored the first try as George Williams showed great feet and a turn of pace to get over. Zak Hardaker missed the conversion, but it was still a two point lead for the Warriors.
The Tigers had chances to get back into it before half time, Ellis missed two penalties, the first from 40m out wide, and then the second, he hit the post from 30m.
They would be made to pay for that in the second half as former Tiger Hardaker successfully chased and grounded his own kick to get a second try for the Warriors. He then converted his own try to bring Wigan into double figures.
That try seemed to settle Wigan down, and they then grabbed a second try in quick succession through Joe Greenwood. Hardaker was off target with the conversion, but it was still a 12 point lead for the hosts, who had that second place in their grasp.
Wigan then moved for the kill and got another try just after the hour as Oliver Gildart got away from a few challenges to score out wide. Hardaker missed the conversion, but it was still a 16 point advantage.
Castleford let their frustrations get the better of them as Jesse Sene-Lefao was sent off for going in with his knees whilst Oliver Partington was on the floor.
The game was then getting slightly heated after that, but Wigan moved to calm the game down as Hardaker added another two points to Wigan’s total.
Wigan then sealed it after a sliding finish from Young Player of the Year nominee Morgan Smithies, his first try in the Super League. Hardaker converted this time to bring Wigan out to 26.
There was just about time for Cas to add a consolation as Cheyse Blair got in after a mistake at the back from a kick for Wigan. Ellis scored the conversion to bring their deficit down to 18.
That result confirms Wigan will be at the DW for the playoffs, they will play either Warrington Wolves or Salford Red Devils.
As for the Tigers, they need a favour from League Leaders St Helens to secure their place in the playoffs.