FOR most of last night, Alexei Eremenko looked like he was going to single-handedly win this match for Kilmarnock.

Then - both literally and metaphorically - he lost it.

On the occasion of his first start of the season, the mercurial Russian-born Finn utterly tormented St Johnstone during the first half, peppering Alan Mannus's goal with shots and being at the heart of countless other openings for his team. It was inventive, box-office stuff.

But the frustrating side to his character soon resurfaced. Things started to go awry when he picked up a needless booking for diving and, when he tried one trick too many in the wrong area, he then compounded his error by tugging back Michael O'Halloran, the resultant red card leaving his side a man short for the last 20 minutes.

They were also a goal in arrears by this point, Brian Graham's deflected finish - his third in four games - after some penalty box pinball enough ultimately to take Tommy Wright's cup specialists one match away from their third consecutive semi final. The home fans howled at referee Steven McLean for his part in it all, and while his inconsistency in dealing with simulation hardly helped matters, his worst offense of all may have been for ruling out a Michael Ngoo headed equaliser for a phantom foul in the box.

"I don't think the sending-off changed the game because we still looked like the team that was going to score, even with 10 men," said Allan Johnston, the Kilmarnock manager. "But obviously the referee has made a big mistake, because we should have been going into extra time. He has said Josh [Magennis] has fouled the guy who was marking him but we have watched it back and there is nothing in it. I don't criticise referees but you can't afford to make mistakes like that."

Johnston made two changes from the eleven which contested a largely uneventful goalless draw with Hamilton on Saturday, Eremenko replacing Robbie Muirhead, and Chris Johnston his fellow academy product Rory McKenzie. There were no survivors from the Ayrshire club's 2012 cup winning squad - Manuel Pascali was at the club at that time, but missed out due to injury - although Josh Magennis had celebrated victory in this competition last year, appearing in Aberdeen's celebration photos despite the fact he was a St Mirren player at the time.

From the moment Eremenko embarrassed Chris Millar with a nutmeg on his first touch, you could tell he was up for the cup. Next was an instinctive shimmy to buy himself a yard and a curling right-foot shot which Alan Mannus had to dive full length to tip behind. Another subtle touch played in Magennis although the big striker couldn't find the target with his finish.

The impressive Mark Connolly forced an alert save from Mannus with a header before another Eremenko long-ranger forced the goalkeeper into action. Before the break, the Finn would spurn his clearest opening of the night, from a Tope Obadeyi pull back, then launch his latest 25-yarder inches wide.

Seasoned watchers of Tommy Wright's St Johnstone team would have known he would not accept this state of affairs for long. Graham, a man whose United team were beaten by St Johnstone in last year's Scottish Cup final, troubled Samson with a header before the home goalkeeper had to dive full length to defy a Dave MacKay free kick.

The promised goal duly arrived. Lee Croft made inroads down the right, Michael O'Halloran's shot deflected off a defender and back off his own face into the path of Graham, whose awkward high volley appeared to take a nick off a defender as it flew high past Samson.

Kilmarnock refused to bow to their fate even after Eremenko's dismissal but it is St Johnstone whose dream of further cup glory lives on. "We take the league seriously but the cup is really our only opportunity to win something as we proved last season," said Wright. "Brian has come in and you couldn't ask for any more than three goals in three starts and one appearance off the bench. And he will get better."