St Johnstone manager Tommy Wright criticised referee Craig Thomson for awarding Celtic a controversial penalty kick in their 5-2 win at McDiarmid Park.

The Perth side went into the break with a 2-1 lead following goals from Keith Watson and an own goal from Dedryck Boyata, cancelling out Liam Henderson's opener.

However, the Scottish Premiership leaders were handed a way back into the match when Thompson pointed to the spot for what he viewed to be a handball by Watson.

Moussa Dembele equalised from the penalty spot before Celtic took a firm grip of the game, with the Frenchman netting a hat-trick to complete a 5-2 win for the Hoops.

The Saints boss said: "There is game changers and certainly there is three big game changers in that second half.

"It is not a penalty. If I live to be 100 it should never be a penalty. How he gives it is beyond me. He couldn't wait to give the penalty.

"I shouted to him (referee) on the pitch and he gestured that both hands were up and it was almost as if he had caught the ball which didn't happen. It hit his hip.

"It does touch his elbow which is held in but you can't see that until you see the camera angle from behind the goal so how can he give it.

"He has to be 100 per cent. It is a game changer. It turned the whole dynamic of the game. It gives a great side like Celtic a massive lift and almost knocked the stuffing out of us.

"Danny Swanson is a penalty. Brendan would be disappointed if that wasn't given. Brown doesn't get anything on the ball, Danny's knee goes inwards so there is contact. It is a penalty. Joe Shaughnessy. The ball is in flight, he is dragged to the ground. He warns the Celtic player. That is a penalty. You don't warn players.

"They are human and they will make mistakes but there are mistakes and glaring mistakes."