|Wigan (0) 20|
|Tries: Davies, Tomkins, Leuluai, Isa Goals: Williams 2|
|Castleford (20) 38|
|Tries: Eden, Trueman 3, Minikin 2, Shenton Goals: McShane 5|
Jake Trueman scored a first-half hat-trick on his first Super League start as Castleford beat Wigan, whose play-offs hopes now hang by a thread.
The 18-year-old went over three times in 18 minutes after Greg Eden's try as Castleford led 20-0 at half-time.
Greg Minikin extended Cas' lead before tries from Tom Davies, Sam Tomkins and Thomas Leuluai gave Wigan some hope.
Michael Shenton and Minikin secured the win for Cas, with Willie Isa scoring a consolation try for Warriors.
Wigan, who won last year's Grand Final, now need results to go their way next week if they are to stand a chance of reclaiming their title going into their final game at Wakefield on Saturday,
Eighteen-year-old Trueman, who was part of the young Castleford side beaten by Wigan in the academy Grand Final on the same ground a fortnight ago, lit up the DW Stadium after he was called up to replace Luke Gale at half-back.
Trueman was part of the move to set up Eden for a fifth-minute opener and needed only 15 minutes to score his first Super League try, as he raced on to hooker Adam Milner's grubber kick.
The teenager pounced on a loose ball to go over eight minutes later and completed his treble when he burst through after spotting a gap in the home side's defence.
Wigan briefly looked like coming back into the game when they scored three times in nine minutes in the second half - the pick of which saw Leuluai jink in for a solo try.
But Shenton glided through the Warriors defence and Minikin went over in the last minute to ensure a comfortable Castleford victory.
It made for a miserable afternoon for Wigan coach Shaun Wane, who had been part of a pre-match parade of the club's victorious 1987 World Club Challenge side.
Wigan coach Shaun Wane:
"I'm embarrassed that my old team-mates saw that. It was way off the standards of a team I coach.
"I'm not sure how much difference he [captain Sean O'Loughlin] would have made. We would have defended better but I never saw that first half coming.
"It came down to poor attitude. We improved in the second half but too many individuals had off days in our biggest game at the back end of the season.
"It's really disappointing. We now need favours off other teams."
Castleford coach Daryl Powell:
"I thought that first half was one of most controlled performances we've had all year, regardless of who was playing.
"I thought all along if we could win today, it would be huge for us and it was an outstanding performance for 60 minutes. We had 20 minutes of madness but it's pretty tough to keep Wigan quiet for 80."
On 18-year-old Jake Trueman: "I thought he was pretty nervous when I said he would be starting but he's handled it pretty well. He showed a lot of maturity for a young fella today.
"I was really pleased with what he is able to do and clearly you'd be confident putting him out in the field whatever the game because he handled that with assurance today."
Wigan: S. Tomkins, Davies, Gelling, Gildart, Burgess, Williams, Leuluai, Nuuausala, McIlorum, Clubb, Bateman, Farrell, J. Tomkins.
Replacements: Sutton, Isa, Powell, Tautai.
Castleford: Hardaker, Minikin, Webster, Shenton, Eden, McShane, Trueman, Millington, Milner, Foster, O. Holmes, McMeeken, Massey.
Replacements: Sene-Lefao, Cook, Springer, T. Holmes.
Referee: Ben Thaler (RFL).