Celtic scored twice in the last eight minutes to beat Alloa Athletic 2-0 in the quarter-finals of the Betfred Cup at Parkhead.
The joint League 1 leaders frustrated the Scottish champions, who passed up several good chances, but Brendan Rodgers' side eventually made the breakthrough when James Forrest beat Neil Parry with a fine finish from 18 yards.
Moussa Dembele added the second goal in the last minute to seal a place in Thursday evening's draw, along with Morton, Rangers and Aberdeen or St Johnstone.
