Walsall looked to be heading for a sixth successive defeat after Adebayo Akinfenwa gave Torquay a deserved lead in the 59th minute with his 14th goal of the season.
But Walsall were saved by Fryatt who pounced to secure a point after 80 minutes - just 60 seconds after he had been sent-on.
It was a cruel blow for Torquay who should have been out of sight by half time only to be undone by poor finishing.
They dominated a one-sided first half from start to finish with the impressive Alex Russell running the show from the heart of the Torquay midfield.
Walsall were pegged back in their own half for much of the opening period only to successfully ride their luck.
But Torquay were undone by their finishing and that came back to haunt them.
Skipper Craig Taylor twice failed to hit the target from close range in the opening five minutes and leading scorer Akinfenwa shot weakly on two occasions when he only had Walsall goalkeeper Andy Oakes to beat.
Such was Torquay's dominance that it was fully 25 minutes before Walsall created their one and only threat of the first half.
But, like Torquay, Walsall lacked a cutting edge and Jorge Leitao volleyed weakly into the arms of goalkeeper Andy Marriott after good work by player-manager Paul Merson.
When Akinfenwa then fired over from close range seven minutes into the second half it looked as though they would never earn any reward.
Unsurprisingly, it needed a mistake by Walsall to gift Torquay the lead.
Akinfenwa chased a hopeful ball by Phillips that looked set to be headed back to Oakes by Ian Roper but the striker muscled his way past the duo and steered the ball into an empty net.
That looked set to be the match winner, but Walsall were finally woken from their slumbers by falling behind.
Marriott and Taylor denied Julian Joachim and Leitao in quick succession, before Merson pulled off his masterstroke to send on Fryatt.
The England youth international was only on the pitch for a minute when he latched on to a knockdown by Darren Wrack to fire past Marriott for his 14th goal of the season.