Celtic secured a narrow but deserved victory thanks to a John Hartson goal in this Old Firm match which for once failed to live up to expectations.
This result leaves Celtic only three points behind their oldest rivals but with a game in hand.
Rangers appeared strangely lethargic throughout and came out second best in most challenges and it was only in some late pressure that they came close to equalising.
After a quiet start Hartson passed up a great chance to put the home team ahead after he shot wide when Stilian Petrov's cross flashed across the face of goal.
Fernando Ricksen and Craig Moore where then booked in quick succession as Rangers struggled to cope.
It was not until the 27th minute that the visitors created their first chance but Mikel Arteta shot wide after Shota Arveladze set up the chance.
Didier Agathe limped off to be replaced by Mo Sylla and a poor first half finished in controversy when Celtic were denied a penalty after Moore appeared to mis-time his challenge on Alan Thompson who had a superb match for the home team.
Celtic stepped up the tempo at the start of the second half and Hartson again squandered a gilt-edged chance when he glanced his header wide from Thompson's cross.
Arteta briefly threatened with a run into the box before Robert Douglas saved a Peter Lovenkrands shot.
Hartson made the deserved breakthrough for Celtic when the Welshman crashed his right-foot shot past Stefan Klos from 12 yards.
It was a well-worked goal with Paul Lambert's pass releasing Thompson in a swift break and from his cross Chris Sutton nodded the ball over for Hartson to finish.
Neil Lennon then went close to adding to Celtic's lead before Lambert just failed to reach Sutton's cross in another attack.
Gers boss Alex McLeish sent on all three substitutes in an attempt to turn the match in his favour.
It nearly paid off as both Arveladze and Lorenzo Amoruso tested Douglas in the Celtic goal but the keeper proved his worth with two outstanding saves as Celtic played out time.