In a match that almost mirrored yesterday's 4 - 3 win for Hibs, Celtic posted the exact same score in their own semi-final against Dundee United to reach the Scottish Cup final.
Kris Commons had given Celtic the lead before Mackay Stevens equalised for Dundee United.
The Tangerines took the lead for the first time when Jon Daly headed in on 30 minutes but Celtic hit back straight away through Victor Wanyama.
Commons got his second goal of the game after half-time to make it 3 - 2 to the Hoops but Daly headed in again to send the game to extra-time.
But it was an Anthony Stokes header which gave Celtic the win midway through extra-time to book a final place against Pat Fenlon's Hibs.