Walsall, with a much younger side than that which had struggled earlier in the season, gave a magnificent display of attacking football to totally outplay disappointing Huddersfield.
And there was further misery for the Terriers when they had skipper Frank Sinclair sent off in the 54th minute following two bookable offences.
Both incidents involved Walsall midfielder Ishmel Demontagnac, who received a yellow card in the first.
But it was not about disciplinary measures, it was about Walsall's superiority in a match where they might have scored further goals.
Huddersfield didn't have a clear-cut chance, the best they could muster being a first minute shot from Matthew Young which went over following a flick-on by the hard-working Luke Beckett.
The Saddlers had a chance in the sixth minute when defender Nathan Clarke left the ball for keeper Matt Glennon only for striker Tommy Mooney to nip in, but Glennon cut down the angle and made a good save.
There was no surprise when Walsall went in front after 31 minutes.
Danny Fox sent over a well-flighted free-kick which Anthony Gerrard met with a fine glancing header.
Walsall deservedly increased the lead two minutes before half-time when Mooney flicked on a pass by Fox and Edrissa Sonko coolly finished.
Man-of-the-match Mark Bradley added Walsall's third goal five minutes after the interval, prodding home from close range when Gerrard turned the ball across goal.
Sinclair's sending off four minutes later was academic in terms of the result and Walsall continued to press forward with hard-working veteran Mooney deserving to notch the fourth goal with a looping header from a cross by Rhys Weston.
Walsall manager Richard Money made substitutions and one of them, another teenager Troy Deeney, broke clear moments from the end, shrugging off Huddersfield's desperate challenges and being unlucky not to score with a shot that went wide off the outside of the post.