The Doonhamers made history with their first win at Tynecastle since 1963 as a Connor Shields brace, along with an own goal, helped Queens on to their first win in three.
Allan Johnston was back in the dugout at his old club and he made three changes to the side that lost at Cappielow. In came skipper Stephen Dobbie, Niyah Joseph and Ciaran Dickson, while Calvin McGrory, Euan East and Dapo Mebude dropped to the bench. There was also a return to the matchday squad for Joe McKee, who has been missing with a calf injury since January.
The South set up in a 5-3-2 formation with Dobbie joining Shields up front, while Joseph slotted into the midfield three along side McCabe and Dickson. Ayo Obileye slotted into the right side of three centre-backs with Buchanan in the middle.
The hosts had Ross Stewart in goals with Craig Gordon on international duty in Israel on Sunday. Liam Smith is with Northern Ireland, although Liam Boyce started for the Jambos at Tynecastle.
After a mauling the last time Queens visited Tynecastle it was vital that they stayed in the game for as long as possible.
But Queens went one better than that, taking the lead less than two minutes in. A loose Mihai Popescu pass was cut out by Dobbie, who played in Connor Shields to fire past Stewart in goals.
Shields opens the scoring
Shields celebrates his opener
It was almost two after six minutes as well as a perfect McCabe ball was met by the foot of Rhys McCabe, although the centre-back fired well over.
Andy Halliday had the first couple of chances for the hosts, seeing from inside the area blocked before Rohan Ferguson saved well from his 18 yard volley.
Queens were playing well though and getting into the Hearts box at will, although it didn?t take Queens getting into the area for them to double their lead.
A beautiful through ball from Joseph was latched onto by Connor Shields, with Queens? top scorer in all competitions chipping Stewart sublimely from 25 yards out.
Shields strikes his second
Goal celebrations
It was an absolute screamer from Queens? talisman who was a threat to Hearts all game.
Despite creating little from open play, the hosts were looking dangerous from set-pieces with Popescu, Christoph Berra, Craig Halkett and Armand Gnanduillet all posing significant ariel threats in the box.
And it was through the Romanian Mihai Popescu that Hearts hit back, with the centre-half making up for his earlier mistake by knocking past Ferguson from a Halliday corner on 34 minutes.
Popescu heads home
Dobbie tested his luck from the edge of the area before Gavin Duncan blew for half-time.
HT: Hearts 1-2 Queens
A near-perfect performance from the Doonhamers who limited the Jambos to very little. Popescu?s headed goal made things tougher for Queens in the second-half though with Hearts likely to be exerting plenty of pressure.
It took until 61 minutes for the hosts to get any real shot away at Queens? goal though with Boyce juggling the ball on the edge of the area before seeing his shot blocked by Obileye.
The South?s first real chance came after 68 minutes when Dobbie?s close range free-kick was well blocked by Boyce.
Just four minutes later though all of Hearts? pressure told. Substitute Euan Henderson delivered a wicked low cross into the path of Armand Gnanduillet to fire home from close range.
Gnanduillet equalises for Hearts
This was to be a real test of Queens? character in the final 15 minutes, but they more than stood up to it.
Mebude replaced Dobbie after 77 minutes to inject pace into the side as both Gnanduillet and Halkett were booked for challenges on Obileye and Mebude.
Despite Hearts being overwhelming favourites to go on and win the game, Championship football just doesn?t work like that.
On 82 minutes Shields picked up the ball on the left before looping a cross into the area that Andy Irving diverted into his own net to put Queens back in the lead again.
Shields and Dickson celebrate as Irving turns the ball into his own net
It was no less than Queens deserved either with an astute defensive performance limited the Jam Tarts to half chances.
But there was still plenty of time left for the hosts to pull one back. And they almost did on various occasions but for the commitment of Buchanan, Obileye and Breen who were blocking everything that came there way.
The scariest moment came on 90 minutes though when Gnanduillet had the ball in the back of the net for the home team, only for the linesman to put his flag up signalling that the ball had went out before it was crossed in.
FT: Hearts 2-3 Queens
58 winless years at Tynecastle come to an end today courtesy of a sensational Queens performance.
A performance that showed bags of character and ruthlessness on front of goal means that the South remain sixth, joint third and only three points from second, although Dundee meet Dunfermline on Saturday night.
It?s cup action at Palmerston on Easter Monday as the green side of Edinburgh travel to Palmerston.
Finlay Jack