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.
Walter Smith's men remain one point clear at the top of the table, though, with Celtic also slipping up.
Joe Ledley saw red for a two footed lunge on Black and Hearts took full advantage to claim three points.