Slipshod Celtic stumbled in this season's compelling William Hill Premiership title race with a damaging 2-0 defeat by Dundee United at Tannadice.
The pressure was on Martin O'Neill's side after leaders Hearts and title-challenging Rangers both won on Saturday and they meekly failed to meet the challenge.
On a poor Tannadice pitch, the Hoops were shaken by a Will Ferry goal in the 51st minute before Emmanuel Agyei drove in a second in the 63rd minute.
The result means an eighth league loss for Celtic this season to leave them in third place, five points behind the Gorgie outfit and two points behind their Old Firm rivals, with seven fixtures remaining after the international break.
United have beaten Celtic twice in a row at home in the league for the first time since April 1991 and it leaves them six points behind sixth-place Falkirk with two fixtures before the split and still with a chance of a top-half finish.
