John Hartson has branded Celtic defender Alexandro Bernabei a "disgrace" after his failure to stop David Watson scoring for Kilmarnock in the recent 1-1 draw at Parkhead.

The dropped points led to Rangers going top of the Scottish Premiership after their victory over St Johnstone.

Bernabei was brought on as substitute for Greg Taylor with 30 minutes left against Derek McInnes' men and was unable to stop Watson from netting a stoppage-time equaliser.

"Bernabei is a disgrace, he doesn't even challenge Watson for the goal," Hartson told GO Radio.

"If you're a left-back in that position, last minute, you are giving everything to stop a goal. That could cost Celtic the title! It doesn't mean enough, it's got to matter more.

"You've got to stop a goal as a defender with your life. It's got to upset you, annoy you. I see Brendan talking really calm, maybe he's had a pop at them in the dressing room.

"But that equaliser should never have been conceded. Kilmarnock will say it was a good goal but it should never have happened.

"You've got to learn to see games out."

READ MORE: Celtic's defence has been posted missing all season

Hartson has slammed the players the club have signed so far this season, insisting they are "coasting".

"Yes, Kilmarnock are doing well but you can't let them get three results against you and still expect to win the league," he continued.

"Some Celtic players wouldn't play for Kilmarnock. They're coasting, happy to be Celtic players and wouldn't play for other teams in Scotland.

"Brendan Rodgers has been missing some first team players. Cameron Carter-Vickers is out. Reo Hatate is out.

"But some of the players who have come into replace them, they are showing that they are just not quite at the level.

"They should be ready to go in and give Brendan Rodgers a headache."