Celtic lost in the Scottish Premier League for only the second time since Oct. 2 on Sunday, 1-0 at Dundee United.

Scott Robertson's first-half header from Dundee United's first real attack was enough to hand Celtic its second league defeat since a 2-0 reverse at Hearts.

The champion's only other defeat in that time was a 3-2 loss at Rangers last month.

Celtic is still 20 points clear of Rangers with one game remaining.

Celtic manager Neil Lennon says ''I was not happy with the attitude of some of the players out there today. Some of them are on holiday mode already.''

Hearts beat St. Johnstone 2-0 in Sunday's other SPL game.