Goals from two contrasting sources eased Saints past stuffy Championship opponents and ensured Perth fans’ dreams of gracing two cup finals will continue beyond the festive season.
High-profile attacker Stevie May enhanced his growing reputation with a 12th strike of the season and Bosnian World Cup hopeful Sanel Jahic celebrated a belated Perth debut with a close-range touch to put paid to Livingston’s hopes of pulling off a cup shock.
The match, played in front of just 2,294 spectators McDiarmid Park’s lowest crowd of the season, was preceded by a minute’s silence to pay respect to victims of the Glasgow helicopter tragedy.
The Perth side showed just one change from the line-up which lost in Inverness, with Jahic being handed his first start since signing a short-term deal in a bid to play his way into Bosnia’s squad for Brazil 2014.
And he capped his first start by being handily placed to stab home a point-blank finish around the hour mark.
“It was my first game for four months and I will get better and better, but I was lucky to score when it deflected off their number six [Martin Scott],” said the Bosnian.
“I want to give my best until January and then we will see what happens. Of course, I want to play but the coach will decide who plays against Aberdeen.”
Jahic knows he has to impress for Saints to have any chance of topping an impressive career by representing his country on the greatest stage of them all.
“I have been in the national team for five or six years and think I have 25 or 26 caps.
“I played a friendly earlier in May against Mexico in the USA when we lost 2-1. But I need to play and to play good to make the list for Brazil. If I play well, I think the coach will call me.”
Saints dominated the tie but home keeper Alan Mannus pulled off several fine saves to preserve a clean sheet and keep the Lions at bay.
The Northern Ireland internationalist conjured up a superb one-handed stop to tip over a fierce Callum Fordyce header from a Martin Scott free-kick in the 15th minute, after Nigel Hasselbaink had tested Kevin Walker at the other end with a low shot on the turn.
Saints secured a 24th-minute lead and there was no surprise at the identity of the goalscorer.
When Murray Davidson flicked the ball on, May took one touch and lashed home a low 20-yard shot into the corner before keeper Walker could respond.
Then advanced midfielder David Wotherspoon dragged an angled shot inches wide of the far post and Hasselbaink embarked on a trademark run, which ended with an ambitious scoop drifting off target from an impossible angle.
Just before the break an alert Mannus was again called upon to defy the combination of Scott, this time delivering from a corner, and an identical flashing Fordyce header.
The keeper was examined again in the 58th minute when he clawed out Mark McNulty’s rising 16-yarder, which was heading for the top corner, and within three minutes debutant Jahic sealed the Perth club’s progress.
Wotherspoon’s in-swinging delivery wormed its way to the Bosnian defender and he bundled it over the line.
Then a breathtaking piece of skill from May almost made it three, with the striker brilliantly controlling and teeing-up a Chris Millar lob with his heel only for keeper Walker to block his close-range shot and deny the centre a “goal of the season” contender.
Hasselbaink should have added to Saints’ tally when he bowled over dreaming defender Coll Donaldson only to smash a shot over the bar after ignoring pleas from two frustrated colleagues for a pass.
With the Championship side throwing caution to the wind, Fordyce wasted an opportunity to set-up a grandstand finish with a shot blazed wide from a partially cleared corner kick and McNulty trundled past a close-range touch after surging into the heart of the Perth penalty area.
In the closing stages, Saints substitute Rory Fallon rose to connect with a deep cross from Dave Mackay but his header crashed back off the crossbar and a looping Simon Mensing header dropped on to the woodwork at the other end.
Saints boss Tommy Wright accepted that Mannus had been influential in the victory but admitted his side had “got sloppy” after both goals.
“We were wasteful, making the wrong decisions. It should maybe have been more comfortable but we are in the hat and that is the main thing.”
Wright hinted that he would like to see Jahic linger beyond the transfer widow.
“He did OK for his first full game. You can see what a good player he is. He is quick and comfortable on the ball. But finances will dictate whether we can keep him beyond January.”
Livingston manager John McGlynn groaned: “I will never know how we didn’t score in the second half. We had chance after chance in the last 10 minutes. It would have made them more nervous if we had got one back but St Johnstone are a quality side and they showed that.”