Graham Carey fired St Johnstone into the Scottish Cup semi-finals with a stunning strike to see off Livingston.
The substitute had only been on the pitch for four minutes when he made his mark with a rasping 30-yard drive that nestled into the top corner.
The 1-0 defeat was harsh on Championship promotion hopefuls Livingston as they were made to pay for their wasteful finishing in a first half they dominated.
Despite not being at their best, it was Saints who were able to build on the momentum from a recent upturn in form in the Premiership.
Saints could have been in front inside two minutes when Stephen Duke-McKenna picked out the unmarked Jason Holt in the box but the former Livingston midfielder miscued his shot and goalkeeper Jerome Prior picked up the bouncing ball.
The chance proved to be the visitors’ only significant foray into the Lions box in the first half after David Martindale’s side created a string of good chances.
Andrew Shinnie’s downward header from Robbie Muirhead’s free-kick was scooped away by the outstretched Andrew Fisher.
Shinne dragged another low left-footed effort wide as Livingston laid siege to the Saints goal.
Saints keeper Fisher was called upon again to push a glancing Danny Wilson header away.
Shinnie then thought he should have had a penalty in the 19th minute after being caught in the face by Daniels Balodis’ flailing arm and, as play continued, Adama Sidibeh tucked away Sam Curtis’ cross. But Sidibeh’s celebrations were cut short after the linesman flagged for offside.
Livingston then carved Saints open with a flowing move that should have culminated in Muirhead opening the scoring.
Stephen Kelly clipped a ball forward to Tete Yengi and the Australian’s back heel inside the area set his team-mate free but Muirhead somehow managed to fire wide from close range with only the goalkeeper to beat.
St Johnstone were happy to hear the half-time whistle and boss Simo Valakari used the break to bring on Drey Wright for Duke-McKenna.
And the Saints substitute was involved immediately when his free-kick to the back post picked out Makenzie Kirk but the striker’s tame header was easily collected by Prior.
Saints were at least having more of a go in the second half and the Premiership team stormed ahead with a wonder strike from Carey in the 73rd minute.
Holt stabbed the ball to his team-mate from Wilson’s headed clearance and the playmaker took one touch before firing an unstoppable 30-yard drive into the top corner via the underside of the bar.
Livingston looked to the bench for inspiration but Saints held on to set up a last-four Hampden showdown with Celtic.
