The Vikings trailed 16-0 until just before the break but then ran in five tries to end their lean spell after a thrilling contest.
Huddersfield led 16-4 at half time with tries from Nathan Mason, Danny Brough and Joe Wardle with two goals from Brough - the Vikings only reply being a touchdown from Corey Thompson.
But Widnes fought back to lead 24-16 thanks to two tries from man of the match Joe Mellor and others from Stefan Marsh and Thompson, Rhys Hanbury adding two conversions.
Jermaine McGillvary touched down for Huddersfield to cut the deficit to four points after 69 minutes but Widnes held on.
It was a successful debut for new Australian forward signing Jack Buchanan, who made his first appearance off the bench midway through the first half.
Huddersfield went into the clash having all lost all seven away matches this season before beating St Helens at the Magic Weekend in Newcastle last week.
Giants coach Paul Anderson again left out Ryan Brierley, with Scott Grix retaining the full-back spot and recent capture Sebastine Ikahihifo making his second appearance.
Widnes, who won 36-18 at Huddersfield in February, made the brighter start in their bid to complete a league double with a surging burst from Mellor but both Lloyd White and Chris Houston were held up close to the line.
Michael Lawrence pulled off two try-saving tackles and Leroy Cudjoe another to keep Widnes at bay.
Huddersfield hit Widnes with a counter-punch, with Brough putting Nathan Mason over from short range to open up a 6-0 lead after 14 minutes.
The Giants went further ahead after an elementary mistake from Widnes when Setaimata Sa was tackled and no Widnes player made any attempt to get behind the substitute to receive the ball at dummy half.
But Brough was alert, nipping in to sprint 80 metres for an opportunist effort.
Wardle added to the Vikings’ troubles after 28 minutes when he plunged over from Jamie Ellis’ pass, with Brough’s conversion stretching the lead to 16-0.
Widnes did manage to cut the gap to 16-4 at the break, with Thompson taking Brown’s looping long pass to go over in the corner.
White lost the ball over the line for Widnes early in the second half but the Vikings hit back with a superb solo try from Mellor, who cut inside Brough to dart 40 metres on a curving run with Hanbury adding the goal.
Play swung from end to end with both sides realising the importance of the next try.
A Grix error put Huddersfield under pressure and it proved costly, Brown and Hanbury combining to send Marsh over for his 50th Super League try.
Hanbury was off target with the touchline conversion to leave Widnes trailing 16-14.
The Vikings went ahead for the first time on the hour when Thompson gathered Mellor’s high kick to kick ahead and notch his second try to make it 18-16.
Huddersfield were making unforced errors, with a Ryan Hinchcliffe mistake leading to Mellor darting over for his second try.
Hanbury, who had missed three of his first four kicks, this time landed the straightforward conversion to put his side ahead 24-16.
Huddersfield threw themselves a lifeline with quick hands along the backs sending McGillvary over in the corner to reduce the deficit to 24-20.
It was still anybody’s game with 10 minutes left to play but the Vikings held their nerve.