Morton0
St Johnstone1
Gary McDonald struck in the 90th minute to book St Johnstone a place in the last four of the League Cup.
It was hard luck on Morton who had put up a stoic effort against their top-flight opponents but Saints will not complain ahead of today’s semi-final draw.
Saints, who beat Championship leaders Hamilton Accies in the last round, showed one change to their starting line-up
Stopper Frazer Wright returned from suspension to take over from Tom Scobbie who started on the bench.
The Greenock side had former Rangers favourite Nacho Novo in attack backed from wide by Dougie Imrie who scored the winner against Celtic in the previous round.
It was a scrappy start to the match.
In the sixth minute an Imrie free kick was met by the head of Morton skipper Mark McLaughlin but Saints keeper Alan Mannus saved the header with some ease.
Midway through the first half, with neither side gaining control, Imrie tried his luck with a speculative shot from 35 yards but although he found the power, the ball flew wide of the target with another drive in the 32nd minute flying straight into Mannus’ arms.
The second half showed plenty of effort from both sides with little to show.
But with extra-time looming, up popped McDonald to seal victory.