The start of the second half of the fourth-round encounter between Inverness Caledonian Thistle and Greenock Morton were held up by more than 30 minutes because of a power failure, but that did not deter the hosts from winning 4-0.
Inverness went ahead on the stroke of half time when Nick Ross found the target from the penalty spot.
Billy McKay headed his side into a 2-0 lead in the 71st minute and doubled his tally in the final minute of normal time.
Then Morton's Scott Taggart was shown a straight red for his challenge on Torbjorn Agdestein deep into injury time inside the box and Aaron Doran converted the resulting penalty.
Results in full: Burton 1-0 Motherwell, Inverness CT 4-0 Greenock Morton, Queen of the South 2-2 St Mirren, Ross County 0-1 Hibernian, St Johnstone 2-0 Livingston