CALLUM DAVIDSON has again rued the self-inflicted wounds that cost St Johnstone dearly as they lost at Celtic Park.

A misjudgement by left-back Callum Booth allowed Anthony Ralston to tee up Giorgos Giakoumakis for Celtic’s opening goal, before his side lost possession cheaply to eventually concede a penalty that Josip Juranovic tucked away.

The Saints manager was disappointed that individual errors had proved his side’s downfall yet again after the disappointing display against Livingston last time out.

"The first half we had a game plan,” Davidson said.

"I watched Celtic a lot and they have really attacking players and they play with a lot of energy and get the ball in the box quickly.

"Apart from one mistake in the first half I thought we did really well, I don't remember Zander's goal being peppered and making save after save, so [we were] pretty disappointed to go down 1-0.

"He just misjudged it. It is unlike Callum. It was a long-range shot that we can deal with and if we deal with that then we don't concede.

"Listen Callum didn't mean to do it, I am not blaming Callum, we got punished for it.

"I don't think Celtic had many chances in the first half but we got punished then the game becomes a little bit harder for us.

"The second half was like cat and mouse we tried to press a little bit higher. I thought we did that and then from our throw-in we give away a really stupid ball and lose possession really easily.”

Davidson also questioned if Celtic’s penalty award for their second goal - when Liam Gordon fouled Joao Jota - was inside the area, saying that referee Nick Walsh was too quick to make his call.

"I watched the penalty back,” he said. “I am still not sure if it was in the box or out of the box but the referee, like Hibs, was very quick to give a penalty against us.”