Georgios Samaras sent Celtic back to the top of the Scottish Premier League for the first time since 5 January, as they followed up their win over Rangers last Wednesday with a nervous win that now puts them two points clear of their Old Firm rivals.
The on-loan Manchester City striker's 56th-minute header proved decisive, though a stoppage-time finish from Aberdeen's Zander Diamond stunned the crowd until it was disallowed. Rangers have three games in hand on the champions but Celtic will hope that the crowded European and domestic schedule will take its toll on Walter Smith's side.
The hosts were forced to make four changes to the side that beat Rangers three days earlier, with match-winner Jan Vennegoor of Hesselink succumbing to injury but the only thing hurt at Aberdeen is their pride.
Jimmy Calderwood described the 4-3 Scottish Cup semi-final defeat by Queen of the South last weekend as the worst moment of his career. Yet the visitors came closer than their hosts to breaking the deadlock. Scott Severin's sumptuous volley from 30 yards after just five minutes deserved to find the net. Instead, the ball hit both posts before bouncing into the arms of the relieved Artur Boruc.
Celtic introduced Paul Caddis for the second half and the teenage right-back made a huge difference to the champions' tempo. Soon after the break, Scott McDonald burst on to Shunsuke Nakamura's pass and tried to poke the ball beyond Jamie Langfield but the goalkeeper got a touch.
The deadlock was broken in the 56th minute by probably the poorest player on the pitch. Samaras's touch had been dreadful but he got his towering frame in front of Andrew Considine to meet Barry Robson's free-kick and powerfully head into the roof of the net.
Celtic should have killed the contest after that but great goalkeeping from Langfield – who denied Scott McGeady and McDonald – kept Gordon Strachan's men on edge.
They required Caddis to deny Lee Miller in the 76th minute with a sliding tackle as the striker faced an empty net and then Diamond had the ball in the net in stoppage time but that was ruled out for a handball by Barry Nicholson in the build-up.