Hibernian produced a morale-boosting comeback victory to further ease the pressure on boss Pat Fenlon.
Stevie May had St Johnstone in the lead after he executed a fantastic drive from outside the box.
However, Hibs forward Paul Heffernan restored parity after Scott Robertson's effort hit the post.
James Collins snatched a winner and the striker's first goal for the club to stretch Hibs' unbeaten record to four Scottish Premiership games.
The Saints had not lost at McDiarmid Park since last November. It was Fenlon's men who inflicted a 1-0 defeat back then and they once again prevented the hosts from taking the three points here.
The Leith side's problem this season has been their profligacy up front but there was no sign of this on Saturday as Heffernan and Collins both scored to give the visitors an important victory.
Fenlon captured Kilmarnock striker Heffernan before the transfer window closed and, in his first start, he provided more impetus up front for the visitors - linking-up well with Collins - and could have added to the strike he grabbed here.
Collins also opened his account from a tight angle which would have given him a boost following a barren spell in front of goal since his move from Swindon Town.
But it was the opposition's striker May who had the hosts ahead with a stunning effort from outside the box.
St Johnstone manager Tommy Wright would have been delighted to hold on to his star man despite advances from Peterborough during the transfer window, with the 20-year-old showing his importance as he grabbed his fourth goal of the season.
Hibs responded well though, as former Saint Liam Craig saw his free-kick cannon off the wall, but the 26-year-old hit an audacious volley on the rebound which was wonderfully saved by Alan Mannus in goal.
Heffernan was mystified about his departure from Rugby Park, but there was no uncertainty about his equaliser as he slotted home from a tight angle.
Robertson had initially done well to get the shot away but his effort cannoned off the post, allowing Heffernan to show his striking instincts as he nipped in and scored.
The Irish attacker had never been on the winning side against St Johnstone in six attempts but the signs were looking good when Collins, from an acute angle, put his side in front.
May had a couple of chances to equalise, with Hibs' shot-stopper Ben Williams denying him.
Steven MacLean was fortunate to stay on the park when he unceremoniously took the legs from Craig later in the second half while Heffernan could have put the result beyond doubt when he had an excellent opportunity to extend the lead, but it was not to matter as Hibs held on for a valuable victory.