Phil O'Donnell's shot opened the scoring for Celtic after three minutes and Vidar Riseth added a second nine minutes later, rising unmarked to head home his first goal for the club since joining from the Austrian side, Linz, three months ago.
Comfortably in control at half-time, Celtic had a Mark Burchill effort ruled out for handball before extending their lead 11 minutes into the second half. Henrik Larsson's powerful downward header was cleared off the line by Dundee's Brian Irvine but cannoned off the goalkeeper, Robert Douglas, who could only watch as the ball squirmed over the line.
At Ibrox on Saturday, it had been left to Sergio Porrini to calm Rangers' nerves with a 71st minute winner. St Johnstone had already missed a penalty, awarded when Colin Hendry handled the ball on the line, and, with the Rangers captain sent off, the visitors forced 11 second-half corners.
Despite that victory, Celtic now have a chance to further close the gap behind Rangers should they win the Old Firm game at Ibrox on 3 January.
Kilmarnock also continued their pursuit of Rangers with a 1-0 win over Hearts. Gary Holt took advantage of a mistake by Gilles Rousset, the Hearts goalkeeper, in the 27th minute to score the goal that keeps the Ayrshire side three points behind Rangers, although the Glasgow side have a game in hand.
It was a typical day's work for Bobby Williamson's men who were tight at the back, restricting Hearts to half-chances while relying on the skills of a revitalised Ian Durrant in midfield.
There is new life at Motherwell, who are making steady improvement under Billy Davies. Their improved form continued as they beat Dundee United 2-0 at Fir Park. Crucially, without an away win in the League for over a year, Motherwell's home form has been instrumental in taking them to fifth place, and only twice this season have they lost in front of their own supporters.
While Davies is improving as Motherwell's manager, Paul Heggarty is making a good case for himself to become the next manager of Aberdeen as the Dons recorded a third-successive win, 2-1 at Dunfermline. Hibernian, the First Division leaders, recorded the best result of the day, a 3-0 win over Ayr United, to give them a six-point lead in the race for promotion.Reuse content