Plymouth reached the FA Cup fourth round for the first time since 2008 by beating Huddersfield’s second string 3-2 at the John Smith’s Stadium.
Argyle skipper Joe Edwards struck the winner midway through the second half after the visitors had twice fallen behind against Carlos Corberan’s makeshift side.
Romoney Crichlow and Aaron Rowe both scored their first senior goals for Huddersfield to twice give the West Yorkshire club the lead in the first period.
But Plymouth, promoted back to Sky Bet League One last season, responded each time through Ryan Hardie and Panutche Camara before Edwards struck their winner.
Huddersfield made clear where their priorities lie this season as boss Corberan made 11 changes to the side which started last week’s home defeat to Reading.
Centre-half Mustapha Olagunju, 19, and 17-year-old winger Pat Jones made their first-team debuts, while Spanish midfielder Alex Vallejo, Josh Austerfield and striker Kieran Phillips all made their first starts.
The Terriers’ youngsters burst out of the blocks as Crichlow got the faintest of touches on Jones’ fourth-minute corner to glance a header inside the far post.
Plymouth, for whom midfielder Tyrese Fornah and defender Jerome Opoku were the only changes, levelled in the 24th minute.
Hardie ran on to Luke Jephcott’s excellent through-ball and kept his composure to fire home into the bottom corner.
Corberan’s youngsters were rising to the challenge and they regained the lead in fine style as Rowe jinked in off the right flank and crashed a rising shot into the top corner.
Plymouth equalised for a second time shortly before the break, taking advantage of some hesitant defending as Camara turned home Danny Mayor’s cut-back.
Town goalkeeper Ben Hamer, making the 350th start of his career, saved brilliantly from Hardie’s angled drive early in the second period.
But Plymouth edged ahead in the 70th minute. Mayor was involved again and after wriggling free on the left, he set up Edwards, who finished with a low shot from close range.
Town sent on new signing Rolando Aarons, who arrived on a permanent deal from Newcastle this week, before Hamer produced another superb save to deny Jephcott.
Both sides made a flurry of substitutions in the closing stages as Argyle threatened to add a fourth goal, but Town boss Corberan will take plenty of heart from the performances of a clutch of his academy prospects.
