Hearts were booed off by their own supporters after suffering a disappointing 2-1 defeat to St Johnstone.
The Jambos have now lost three league games on the bounce as their terrible form - no wins in 15 attempts - at McDiarmid Park continued.
Ali Crawford fired the Saints ahead within 60 second but Nathaniel Atkinson responded quickly as he equalised for Hearts on six minutes.
But Robbie Neilson's side were second best for the majority of the game and Jamie McCart headed home the winner for the Perth side on 56 minutes.
Saints made four changes to the side that drew 1-1 at Aberdeen in midweek as goalkeeper Zander Clark, Jacob Butterfield, Callum Booth and James Brown were replaced by Elliot Parish, Tom Sang, Tony Gallacher and Murray Davidson.
There were also four alterations to the Hearts team that began last weekend's Scottish Cup tie against Livingston as goalkeeper Craig Gordon, Michael Smith, Andy Halliday and Beni Baningime dropped out to make way for Ross Stewart, Nathaniel Atkinson, Peter Haring and Josh Ginnelly.
Saints took the lead within the opening minute when Ali Crawford pinged a precise shot into the corner of the net from just inside the box after a lovely flowing build-up involving Glenn Middleton and Melker Hallberg.
Hearts equalised in the sixth minute when Atkinson followed up to fire in the rebound after Barrie McKay's shot from the edge of the box came back off the outside of the post.
The visitors almost went ahead in the 11th minute when Ellis Simms knocked the ball against the post from close range after the hosts failed to deal with Stephen Kingsley's corner.
Saints threatened in the 20th minute when Davidson fired a low shot just wide from the edge of the box.
Crawford then saw an effort deflect wide off Atkinson in the 40th minute as the first half ended all square.
Saints went close two minutes after the break when Hallberg curled a shot just past the post from 25 yards out.
At the other end, Simms hooked a decent chance over the bar from a Ginnelly cutback in the 48th minute before the big Hearts striker glanced a header wide moments later.
Saints went ahead in the 56th minute when McCart rose to nod home an in swinging free-kick from Hallberg.
Hearts defender John Souttar saw a close-range header brilliantly pushed out by Parish from a Kingsley corner in the 63rd minute.
The visitors put the pressure on in the closing stages but the closest they went to an equaliser was a Souttar header that came back off the crossbar.
