Motherwell compounded a miserable week for Hearts with victory at Tynecastle.
The hosts, who parted with manager John McGlynn in midweek, fell two behind early on as Michael Higdon and a Dylan McGowan own goal put 'Well in command.
Hearts rallied in the second half and pulled one back through John Sutton's header just before the hour mark.
But the visitors were resolute and consigned the home side to a fifth straight defeat - a disappointing start for interim boss Gary Locke.
The Steelmen, who remain second in the Scottish Premier League are now three points clear of Inverness.
After slipping to second-bottom in the league the day before McGlynn's departure, the last thing Hearts needed was a sloppy start.
Indeed, it was worse than that as Stuart McCall's side netted twice in the opening eight minutes.
Higdon happened upon a loose ball after James McFadden had tried to force his way through a couple of challenges and the big striker rattled the ball past Jamie MacDonald from outside the box.
And then the unfortunate McGowan diverted over his own goal-line from Nicky Law's rebound effort, the midfielder's initial effort having been blocked by MacDonald.
Facing such an uphill task, the hosts needed their experienced players to show some leadership and Mehdi Taouil tried to oblige with a curling shot wide.
Hearts' defensive vulnerabilities were exposed again when Higdon bustled through and rounded MacDonald but Andy Webster was well placed to clear the eventual cutback.
Michael Ngoo had looked lively for with a couple of headers for the home side and the on-loan Liverpool striker tested Darren Randolph with a superb shot on the turn, the Motherwell keeper reacting well to parry out for a corner.
The home side needed a break and an aggrieved McCall may feel they were given one in the build-up to the Sutton goal.
The Motherwell boss was unhappy his team were not awarded a throw-in before Arvydas Novikovas won and delivered the corner from which the former Fir Park favourite nodded home.
Hearts were galvanised and a scramble in the box ended with Ryan Stevenson's shot blocked by the legs of Randolph.
But that was as close as Locke's side came to a leveller as Motherwell made good use of possession to frustrate their hosts in the closing stages.