Stuart Armstrong's close-range strike has given Dundee United the lead at Celtic, although the Scottish Premiership pacesetters have squandered several first-half chances.
The hosts almost went ahead in the opening minutes but Anthony Stokes was unable to keep his early effort on target.
United posed an attacking threat of their own with Fraser Forster being called into to deny Gary Mackay and Brian Graham in an open game.
Although the Tangerines enjoyed lots of possession, Celtic had plenty of chances throughout the first 45 minutes to break the deadlock.
Their best chance fell to Charlie Mulgrew, who latched on o Emilio Izaguirre's pinpoint cross but directed his header straight at Radoslaw Cierzniak.
United's goal came seven minutes before the interval with Nadir Ciftci supplying Armstrong on the edge of the six-yard box to coolly slotted home.
Should United hold on, then they could climb further up the Premiership table, having started today in fifth place.
