Simo Valakari will have enjoyed his first stint on the bench as St Johnstone manager after Nicky Clark's late strike sealed all three points for the visitors.
Simon Murray gave Dundee a first half lead after a bizarre defensive gaffe before substitute Graham Carey's superb strike levelled things up.
A SIX MINUTE, 30 SECOND VAR review for the winning goal could only postpone the jubilant Perth celebrations at full time.
It is the first back-to-back league wins for St Johnstone in two years.
The team was unchanged from the side that beat Ross County 3-0 the previous weekend with Clark supporting the attacking partnership of Adama Sidibeh and Benji Kimpioka.
Midfielder Cammy MacPherson remained unavailable and striker Uche Ikpeazu also missed out as he continues his recovery to full fitness.
Valakari's blueprint was noticeable from the start with Saints players attempting to pass out from the back through the Dundee press.
There was no goalmouth action to speak of before Saints fell behind in calamitous fashion on 12 minutes.
It looked for all the world that Jack Sanders would get to Dundee goalkeeper Trevor Carson’s long ball first as Saints shotstopper Ross Sinclair rushed off is line.
But up popped Simon Murray who nicked in first, poked the ball high into the air and awkwardly chested home leaving Sinclair and, in particular, Sanders red faced.
Sinclair somewhat redeemed himself just moments later, preventing a Dees second with his foot from a Ziyad Larkeche strike.
Sidibeh found himself clean through on 35 minutes but instead of picking his corner his attempt to round Carson was thwarted and his chance was gone. He should have buried it.
Saints didn’t want the half to end as their momentum was building. An
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