Rangers goalkeeper Allan McGregor saved a late penalty from Georgios Samaras as the Old Firm draw a blank in their Clydesdale Bank Premier League clash at Ibrox.
McGregor had made saves from Daniel Majstorovic, Charlie Mulgrew and Emilio Izaguirre before Celtic substitute Anthony Stokes, on for Gary Hooper, won a spot-kick inside the final 10 minutes.
The Scotland number one dived to his left to save the Greece international's effort to keep second-placed Celtic a point behind with a game in hand.
The game took place against a background of heightened security after a parcel bomb was recently sent to Celtic boss Neil Lennon. However, despite calls for calm, there was still a deafening din inside Ibrox at kick-off time.
There was great drama in the 81st minute when Celtic were awarded a contentious penalty when Celtic substitute Stokes clashed with Steven Davis inside the Rangers penalty area.
Samaras, who had scored a penalty in the 2-0 win at Ibrox at the start of the year, saw his spot kick brilliantly saved by McGregor who dived to his left to push the ball round the post.