Rangers lost in the SPL for the first time this season whilst Celtic also slumped to defeat. There was no movement at the top of the Scottish Premier League as Rangers went down 3-0 to Hibernian at Ibrox and Celtic were beaten 2-0 at Hearts.
It was the first time since May 2007 that the Old Firm sides both lost on the same day.
The Easter Road side stunned its host thanks to goals from Liam Miller, John Rankin and Francis Dickoh, to give Hibs boss Colin Calderwood's his first victory as manager.
Walter Smith's men remain one point clear at the top of the table, though, with Celtic also slipping up.
Goals by Ian Black and David Templeton gave Hearts victory over 10-man Celtic at Tynecastle as Hoops boss Neil Lennon was sent to the stand.
Joe Ledley saw red for a two footed lunge on Black and Hearts took full advantage to claim three points.
