The legendary crooner admits he’s never been more pessimistic than on Monday after seeing his side crash into the Betfred Cup.
But Sir Rod admits his real angst comes from watching the wild scenes that followed the 2-0 loss to Ross County as fans walked to Parkhead to let off steam at Lennon and the board.
Speaking to talkSPORT: “I’m sorry and disgusted.
“All my years supporting the Celts, I’ve never seen anything like it, missiles launched at players, it’s a shame that it makes the club look irresponsible.
“It’s a proud old club and I’m absolutely heartbroken not only with yesterday’s result but all around. ”
And Stewart insists he would stay with the 49-year-old because he doesn’t think the team he loves could find a box office replacement due to his current situation on the pitch.
He added: “Unless there was someone lined up to take Lenny’s place, I don’t think anyone would take him with a bargepole, I really wouldn’t.
“Take control of Celtic, halfway through the season, 11 points behind Rangers, it takes a tough man to do it.
“I would let Lenny end the season, I still think he can turn the tide. We need more players to arrive.
“But I am shocked, shocked, shocked.
“I don’t think there is anyone who can take his place. I don’t think the guy from Bournemouth would touch it, really not. ”