The fates decreed that this blow came after 13 SPL games but it was not luck that went against Hearts but the stupidity of their top earner, Edgaras Jankauskas, whose foolish second-half red card allowed Guillaume Beuzelin and Garry O'Connor the space to inflict two goals in the final 12 minutes.
Hearts remain top, but Celtic could alter that at Dundee United today. Hibernian, meantime, are six points clear of the toiling champions, Rangers.
It has been a traumatic week off the pitch since George Burley's abrupt departure last Saturday. Yet it had not disturbed his former side's momentum one bit as Hearts collected six points from two games.
The appearance of Claudio Ranieri in Edinburgh 48 hours before this derby had hinted at a dramatic twist to the affair. However, the former Chelsea manager's wage demands - Ranieri is reported to have wanted £2.5 million to end his managerial sabbatical - were not well received at Tynecastle.
"It's getting increasingly unlikely," said the Hearts chairman, George Foulkes, when asked yesterday if Ranieri was favourite to take over. "It has more to do with the wage structure. We want to pay well but it is also important for the management team to have a bonus incentive." Foulkes also insisted another interviewee, Sir Bobby Robson, remained a "serious candidate".
The only incentive that the players need in an Edinburgh derby is victory. Although the first half was goalless, that did not reflect the quality of play. The second half was equally gripping, with the vigilance of Robbie Neilson rescuing Hearts twice to deny O'Connor and Derek Riordan, and then Paul Hartley carving Hibernian open after a sublime exchange with Rudi Skacel, only to shoot at Zbigniew Malkowski.
However, the contest turned on a moment of folly by Jankauskas. The experienced acquisition from FBK Kaunas had already been booked when he reacted to a foul by Scott Brown, and angrily shoved his opponent back to earn a second caution and a costly red card.
Hibernian laid siege to Craig Gordon's goal and the leaders finally broke in the 78th minute. Gary Caldwell threaded a clever pass to release Ivan Sproule and the substitute's ball across the face of the box was stabbed in by Beuzelin off the far post.
Two minutes later, the success was sealed when the impressive David Murphy showed great intelligence to pick out O'Connor, who chested the ball down and then drilled a low shot past Gordon to spark intense celebrations around three sides of Easter Road.