Dunfermline shocked title favourites Hearts to win 2-1 at East End Park and go top of the Championship table.
The Pars, via quick-fire second-half strikes from Dom Thomas and Euan Murray, leapfrogged rivals Raith Rovers in the standings to blow the second-tier title race wide open.
A Stephen Kingsley header pulled one back for the visitors but it wasn’t enough as the three points stayed in Fife.
The Pars showed five changes from their 3-2 Betfred Cup win over Clyde last Saturday with Owain Fon Williams, Lewis Mayo, Steven Whittaker, Kyle Turner and Thomas coming into Stevie Crawford’s selection.
For the Jambos, Craig Gordon, Michael Smith, Craig Halkett, Kingsley, Andy Halliday, Liam Boyce and Steven Naismith all returned to give Robbie Neilson’s side a strong-looking starting XI.
Pars set the tone but Jambos still have plenty chances
With the match underway for a fleeting moment, Kerr McInroy launched into Olly Lee with a thunderous challenge as the Fifers set the tone for the occasion.
It seemed even this division’s finest, of which Dunfermline can consider themselves a part going by early season form, will be more than prepared to harangue title favourites Hearts.
However, the men from Gorgie often seemed to have an effective rebuttal for the pressing and harassment of the hosts.
Midfield generals Lee, Halliday and the unorthodoxly-positioned skipper Naismith remain composed and free of fluster as they marshalled proceedings.
Mihai Popescu, however, didn’t get the memo about the sheer nuisance that is Pars frontman Declan McManus.
His barely-legal barge on the Romanian defender led to Turner curling a left-foot effort narrowly astray of Gordon’s goal on 10 minutes.
Popescu nearly got revenge for the man-handling a few minutes later as he crashed a header off Fon Williams’ crossbar from a pinpoint Frear free-kick.
At the other end, Pars midfield anchor Whittaker latched onto Thomas’ delivery and clipped into Gordon’s side-netting after the Scotland goalie needlessly conceded the corner.
On 21 minutes, like he did twice against Dundee on opening day, Kingsley attempted to curl home a deadball but, this time, could only steer his effort past the post.
Mayo, Whittaker and Ryan Dow’s neat interplay was causing the capital club problems down their left side. However, entering the second quarter of the clash it was very much an even contest.
Frear, offside, skewed wide for Hearts while Whittaker saw a volley charged down bravely by Popescu as the teams exchanged blows.
Celtic loanee McInroy was impressing in the middle, covering swathes of the East End Park surface, trying to suffocate Hearts.
However, the Edinburgh outfit did find room to breathe in little pockets, with Boyce acting as a focal point for their circulation of the ball.
Lee blasted a stinger wide on 32 minutes before dazzling Thomas footwork picked out Dow but he could only scoop over.
Going into the half, Gordon terrifically denied Pars captain Murray from close range before being flagged offside and Naismith fired through a crowd in the box but into Fon Williams’ grateful arms.
Craig Wighton joined Boyce up front for the second period as Neilson altered his side to a traditional 4-4-2.
Quick-fire second-half double gives Fifers control
No system or formation could stop what happened next, however, as the Pars opened the scoring on 49 minutes via a Thomas rasper.
Chopping in from the right, the winger fired into the top corner from the edge of the area, aided by a huge deflection off Popescu’s knee leaving Gordon stranded.
Dunfermline smelled blood and continued their assault on the Hearts 18-yard box as they made it 2-0 on 54 minutes through Murray.
From Thomas’ corner, the Pars captain rose highest and nodded home powerfully to give Stevie Crawford’s side an increasingly-comfortable cushion.
Frustration was growing among the visiting ranks as substitute Jamie Walker went into Don Robertson’s book for a cynical foul.
On the hour mark, the Jam Tarts had a glorious opportunity to get back into the match as Northern Irishmen Smith and Boyce linked up with the latter twice denied in acres of space in the box by Fon Williams.
A succession of corners eventually saw Popescu crack the crossbar again, this time from a Halliday delivery.
The excellent McInroy had a decent opportunity to extend the home side’s lead further but could only drag his long-range strike wide.
Racing free on 70 minutes, Hearts skipper Naismith, with the goal gaping, inexplicably elected to pass to the onrushing Jordan Roberts as Dunfermline tracked back and the chance to pull one back was gone.
Soon after, McInroy fired wide once more, before the Pars passed up a gilt-edge opening to make it three as McManus and Mayo couldn’t convert from close range.
Hearts pulled one back with six minutes remaining as Kingsley connected with substitute Andy Irving’s corner to nod past Fon Williams.
However, it wasn’t enough for the men in Maroon, who couldn’t find an equaliser despite five minutes of added time, as they remain third.
Dunfermline Athletic (4-4-1-1): Fon Williams (GK); Mayo, Watson, E Murray (C), Edwards; Dow; Whittaker, McInroy, Thomas (F Murray 84); Turner; McManus (O’Hara 83).
Subs not used: Gill (GK), Comrie, McCann, Wilson and Bowman.
Hearts (4-1-4-1): Gordon (GK); Smith, Halkett, Popescu, Kingsley; Halliday; Wighton (Roberts 63), Naismith (C), Lee (Irving 75), Frear (Walker 52); Boyce.
Subs not used: Stewart (GK), White, Berra and Brandon.
Referee: Don Robertson.