Celtic lost ground in the race for the SPL title as they could only draw 1-1 with Dundee at Dens Park.
Celtic opened the scoring with 11 minutes played when Momo Sylla's cross was headed back across goal by John Hartson and Alan Thompson was on hand to nod past Julian Speroni from five yards.
With 20 minutes played the home side were level.
Ex-Celtic player Mark Burchill scored his first goal for the Dark Blues after brilliant play by Fabian Caballero down the left set his strike partner up six yards from goal.
Henrik Larsson headed a through ball to Hartson running in on the Dundee goal with half an hour played, but the big striker's powerful shot was well saved by Speroni.
Moments later Burchill was denied his second when Javier Sanchez Broto saved his close-range shot.
Barry Smith almost gifted Celtic a goal on the stroke of half time, but his ball straight to Larsson went unpunished as Stilian Petrov took too long to get the final shot in and the danger was cleared.
Hartson headed wide of the Dundee goal three minutes into the second half.
Five minutes later Thompson's free-kick into the danger area was missed by everyone and the ball sailed past the far post.
Steve Lovell fired over the crossbar for Dundee from 20 yards out with 70 minutes played.
Ten minutes from time a good flashing header by Hartson was deflected just past the post and a good save by Sanchez Broto in the Celtic goal denied Gavin Rae with seven minutes to go.
With the two minutes of time added on almost up, Dundee sub Steve Milne was denied a dramatic winner when Sanchez Broto turned his drive around the post for a corner.