It means both sides will meet in a replay at Parkhead early next month.
Both sides ended with 10 men as they fought out an enthralling fifth-round draw at Ibrox.
The home side took the lead inside three minutes from a good strike by teenage midfielder Jamie Ness.
Kris Commons equalised on 17 minutes, before Celtic goalkeeper Fraser Forster was sent off as he conceded a penalty, which was scored by Steven Whittaker.
Scott Brown levelled with a curling shot, then Rangers’ Steven Naismith got a second caution for cheating – throwing himself to the ground in a laughable attempt to win a penalty.
Both sides had chances to win it – with Samaras shocked when he missed a header from two yards out.
Celtic had a massive share of the game – 59% of possession – and twice as many attempts at scoring.
Lennon said after the game: “We were unlucky not to win the game. We were always liable to get caught with 10 men but we played well.”
Asked about seven Old Firm games this season, he laughed: “That’s all I need!”