Castleford gained revenge for their heart-breaking Challenge Cup defeat by grinding out their first win at Huddersfield for five years.
The Tigers produced a huge defensive effort to end their five-match losing run at the expense of the Giants, who dominated the match for long periods but could not find a cutting edge until it was too late.
The Giants, boosted by the return of England pair Eorl Crabtree and Scott Moore, had already gained two wins over the Tigers this year but they produced a disjointed performance to lose more ground on the Super League leaders.
Castleford, still hurting from their dramatic 16-14 Cup defeat at the Galpharm Stadium three weeks ago, made the best possible start with a try after four minutes.
Full-back Richard Owen got loose forward Joe Westerman racing into a gap in the Giants defence on halfway and right winger Kirk Dixon finished strongly at the corner.
Huddersfield were strangely out of sorts and went further behind on 16 minutes when full-back Brett Hodgson's pass was picked off Cas scrum half Ryan McGoldrick and he was left with an unopposed 40-metre run to the line.
Dixon's conversion made it 10-0 and that briefly sparked the home side into life.
Substitute Liam Fulton showed some nice creative touches and breaks by wingmen David Hodgson and Leroy Cudjoe promised much while their best chance was created by scrum half Luke Robinson, who found a chink in the visitors' defence and had two men in support but made a hash of the final pass.
Dixon extended his side's lead on the stroke of half-time with a penalty after substitute Danny Sculthorpe, making his home debut for the Giants, was punished for holding down in the tackle.
Huddersfield continued to create chances in the second half and stand-off Kevin Brown raced clear after taking an offload from Moore only to be brought back for a forward pass.
The Giants put their kicking game to good use to force three successive goal-line drop-outs but still the Castleford line held firm.
Both David Hodgson and Paul Whatuira produced thrilling breaks for the home side down the left but each time the touchline came to the Tigers' rescue and ironically it was only when Huddersfield shifted the attack to the right that they finally found some joy.
Brown and Robinson worked the ball out wide and Simon Finnigan and Stephen Wild combined to get Cudjoe over at the corner on 66 minutes.
Brett Hodgson added the touchline conversion to bring his side to within a converted try but Tigers hooker Rangi Chase made sure of the points with a drop goal three minutes from the end.