A Nikolay Todorov goal nine minutes into the second half was enough for Championship Airdrieonians pull off a shock and knock Premiership outfit St Johnstone out of the Scottish Gas Scottish Cup with a 1-0 win.

Todorov pounced from 10 yards to score his fourth goal in as many matches after Liam McStravick’s cross was hooked back in at the far post.

St Johnstone should have heeded the early warning signs after a poor backpass by Saints Midfielder Graham Carey let in home captain Adam Frizzell.

He ran into the box and got a shot away but it produced a superb save from Bulgarian goalkeeper Dimitar Mitov, who dived low to his right-hand side to keep it out.

Airdrie had claims for a penalty when a low cross from the left came off a St Johnstone player inside the area but referee Kevin Clancy quickly turned down the appeal.

St Johnstone had chances and new signing Benjamin Kimpioka thought he was going to mark his debut with a goal when he rounded Airdrie keeper Josh Rae, but the Swedish striker ran out of pitch as he tried to find the back of the net.

In the second half, Mason Hancock header over Charlie Telfer’s free-kick, before Todorov fired home from inside the area to put Airdrie 1-0 up.

Craig Levein’s side pressed for an equaliser with striker Kimpioka racing through on goal, but Rae was quickly off his line to tackle him. Kimpioka went down under the challenge but referee Kevin Clancy was not interested.

Carey then had a 20-yard strike saved by Rae as the home side held on.