The Perth side played most of the second half two men short after Chris Millar was ordered off, joining Steven Anderson who was red-carded in the first half.
It took the Perth Saints 10 minutes to weather the home storm and in a quick break upfield, Gregory Tade's cross picked out the unmarked Liam Craig but he could only guide his header over the bar.
Craig did better after 14 minutes when he nodded on Callum Davidson's cross into the path of Murray Davidson, who rose high above Lee Mair inside the six-yard box to head the ball past Craig Samson and open the scoring.
Both sides were determined to press forward and the next opening came the visitors' way. Steve MacLean's 25-yard drive was curling low inside the left-hand post until Samson, at full stretch, palmed the ball round the post.
Craig then volleyed an inviting cross from Millar over the bar as St Johnstone chased a second goal.
At the other end Guy evaded a challenge from Anderson but from 15 yards he hoisted his shot over the bar.
Then after 37 minutes the same players tangled at the edge of the box but this time as Guy moved towards the penalty area he was tripped by Anderson. As the last man, referee Bobby Madden had no option but to show the St Johnstone defender a red card.
The Paisley side came close to grabbing the equaliser when Kenny McLean's free-kick was deflected off the defensive wall, forcing Alan Mannus into a superb one-handed save to turn the ball away.
An action-packed first half ended where it started, with Teale again the provider to set up John McGinn. But after creating space for himself at the edge of the box the young midfielder was unlucky to see his thunderous drive rebound from the face of the crossbar.
A defender down, St Johnstone took the half-time break to rearrange their line-up, bringing on Tam Scobbie at the expense of Rowan Vine. Conversely, Danny Lennon used the extra man advantage by replacing Marc McAusland with the attack-minded Dougie Imrie.
McGinn was at the heart of most of the action and when he was tripped by Chris Millar after 67 minutes, the St Johnstone man was shown his second yellow card reducing the visitors to nine men.
From the resultant free-kick, Kenny McLean's brilliant drive was matched by Mannus, but having pushed the ball wide of his goal the keeper was beaten as Paul Dummett lashed the ball high into the net for his first goal for the club.
Mannus was the visitors' hero after 77 minutes when David van Zanten's shot from 20 yards was net-bound until the keeper beat the ball away.
But the keeper had to thank Wright for saving a point four minutes from time. Steve Thomson seemed certain to score from six yards but as the ball thundered toward the net, Wright slid in to boot clear and leave the scores level at the end of a pulsating match.