Huddersfield booked their place in the Super 8s with a storming 32-18 triumph to stun hosts Castleford on Friday night.
England winger Jermaine McGillvary led the visitors' charge with a well-taken hat-trick to deny the Tigers the chance to move up to second in the Super League table, with one week of the regular season remaining.
Castleford tore straight into a Huddersfield side that initially looked way off the pace, racing into a 12-0 lead within 10 minutes.
The hosts opened their account after seven minutes when two soft Giants' penalties gave Jamie Ellis the chance to step through against his former club for a try he also converted.
And the lead was doubled less than three minutes later when Paul McShane's blindside burst bamboozled the visiting defence and won him enough space to feed Michael Shenton, who sent Jake Trueman strolling over.
But that converted score sparked the Giants into action.
Midway through the half they halved the deficit when Danny Brough's long pass enabled Leroy Cudjoe to put McGillvary over in the corner, with Brough landing the touchline conversion.
Then minutes later, Jordan Rankin and Adam O'Brien combined superbly for Cudjoe to send McGillvary over for his second.
A disappointed Daryl Powell pours over Tigers defeat to Huddersfield
Although Brough failed to add the extras, he was on target with a 32nd-minute penalty to level the scores at 12-12.
McShane's neat pass put Junior Moors over from close range four minutes later and converted try number three to restore Castleford's lead, somewhat against the run of play.
But on the stroke of half-time, Brough worked his magic to release Lee Gaskell to dummy his way over and the playmaker goaled to make it 18-18 at the break.
And within four minutes of the restart, the visitors were ahead for the first time when the Castleford defence failed to react to a Brough grubber and Cudjoe made them pay by touching down in the corner, too far out for the scrum-half to
add the extras.
With the Giants in the ascendancy, it was no surprise when they further extended their advantage with a cracking try after Rankin's long, looping pass which put McGillvary over to complete his treble.
McIntosh 'bombed' a golden chance to extend the lead on the hour by taking the wrong option on the half-way line, while Greg Eden was denied a try by the video referee two minutes later.
Huddersfield found the perfect response as Brough banged over a penalty moments later to take them three scores ahead and from there, they were never going to be caught.