Lee McCulloch's dramatic late equaliser in the Old Firm derby at Parkhead kept Rangers seven points clear at the top of the Scottish Premier League.
After Celtic had missed numerous chances and had a Marc-Antoine Fortune goal controversially ruled out by referee Steve Conroy in the first half for his challenge on Gers keeper Allan McGregor, Scott McDonald came off the bench to open the scoring with a 79th-minute header.
It looked like the Hoops would get their just rewards for their part in an unusually one-sided game between the Glasgow giants.
However, two minutes later, in a rare Rangers attack, McCulloch headed a Steven Davis corner past Artur Boruc to give the visitors an undeserved but welcome point.
Sunday's other SPL game also finished 1-1 as Hibernian and Hearts finished with 10 men apiece in a pulsating Edinburgh derby at Easter Road.
Eighteen-year-old Gordon Smith wrote his name into Tynecastle folklore by handing the visitors the lead on his Scottish Premier League debut but Anthony Stokes equalised nine minutes after the restart with his 11th goal of the season.
That was almost immediately followed by red cards for Ruben Palazuelos and Darren McCormack after the latter appeared to headbutt the Spaniard.
