Fryatt inspired Walsall's amazing comeback after Huddersfield had stormed into a two-goal lead in the opening 11 minutes.
The win was a big relief for player-manager Paul Merson who master-minded Walsall's second win in seven games.
But Walsall couldn't have made a worse start when they found themselves two goals in arrears in the opening 11 minutes and there were visions of a repeat of the 5-0 drubbing suffered at Colchester earlier in the week.
Merson gave the Saddlers a glimmer of hope with only his second goal of the season but these hopes nose-dived when the Terriers obtained their third goal in the 33rd minute.
Shell-shocked Walsall, who relied a great deal on Merson, bravely battled back from this seemingly impossible situation to salvage a much needed win.
Earlier Huddersfield exploited Walsall's short-comings particularly in defence where veteran Neil Emblen always struggled against a three-pronged attack which, on this occasion, paid handsome dividends.
They were boosted when Andy Booth latched on to a miserable mistake by Julian Bennett to open Huddersfield's account after just seven minutes.
On-loan Luke Beckett nudged home a close-range second goal in the 11th minute to drop a huge cloud on Walsall's hopes staging a revival.
Merson, however, was on target in the 15th minute with a powerful drive which went in off the post but Beckett popped up at the far post to notch his fourth goal in three games since his arrival from Sheffield United.
Unfortunately, the goal highlighted Walsall's deep-rooted problems. A corner from Rob Edwards was headed on by Booth to the lurking Beckett at the far post.
In a frantic finish to the first half Fryatt again lifted Walsall's hopes with a speculative 30-yard shot which looped past goalkeeper Paul Rachubka.
Four minutes into the second half Walsall were on level terms when Fryatt converted a penalty after Efe Sodje handled on the edge of the area.
Merson set up Walsall's 74th minute winner with an accurate low through pass which Fryatt put away with a precise low shot past Rachubka.