Today's result is up there with Bratislava as one of the worst in the club's history.
Full credit must be given to Clyde, who thoroughly deserved their win. They showed Celtic up in every department and made us look like the First Division side.
It was Roy Keane's first game as a Celtic player, and he must really be scratching his head, wondering what he has got himself into.
With Bobo Balde away on African Nations Cup duty, there was also a debut for Chinese defender Du Wei. Unfortunatley, he was substituted at half time after a disastrous opening period. I would be surprised if he isn't on his way back to China as I write this. He is too lightweight, clumsy and generally not good enough to be a Celtic defender.
Clyde had a goal chopped-off after 15 minutes when Du Wei appeared to be all over the place, had the ball taken from him and slotted into the net by Clyde's Tom Brighton. Luckily for Celtic, referee Kenny Clark judged Brighton's challenge on Du Wei to be a foul and the goal was disallowed, however, replays showed this to be a poor decision and the goal should have stood.
Clyde had another goal chalked off, this time correctly, for offside. Alarm bells were ringing in the Celtic end.
Meanwhile, Celtic were doing absolutley nothing.
On 33 minutes, Clyde took a deserved lead when Bryson finished past Artur Boruc from six yards out.
Boruc was to save Celtic moments later, with a fantastic save from a Stephen O'Donnell penalty. Not surprisingly, it was Du Wei who gave away the penalty, and the 'defender' was lucky not to be sent off.
Clyde doubled their lead on 37 minutes when the Celtic defence looked lost when attempting to defend a corner, and Celtic were punished again.
At half time, the Celtic supporters knew that if the team put in a performance like the second half show at Tynecastle last week, we would at least find ourselves with a replay.
However, it was not to be. Celtic were dire again and despite Du Wei being replaced by Adam Virgo, who played well, things were still shaky at the back.
Stephen McManus was having another stinker, as were Ross Wallace and Paul Telfer, who gave away every ball they were in possession of. It wasn't long before Wallace was substituted, being replaced by Aiden McGeady. Stephen Pearson went to left-back.
Boruc made a cracking save and Clyde came close again, hitting the post. Celtic's best chance came from McGeady, who was practically one on one with the goalkeeper, and couldn't even get his shot on target.
Maciej Zurawski was brought on for the ineffective John Hartson and the Pole got his name on the scoresheet, with a strike that gave the away side a little bit of hope for the remainder of the game.
But Clyde held out for a deserved victory. They will now play Gretna at home in the next round of the cup.
In truth, a defeat like this has been coming for a while. We are constantly giving teams goals of a start (Aberdeen, Inverness, Hearts). Our defence has been absolutley shocking when teams run at us, and that is why today's defeat doesn't surprise me.
Ross Wallace is NOT a left-back and never well be. He should never play there again. Paul Telfer is too slow and is never fit to be a Celtic player. Stephen McManus has been garbage since the issue of his contract situation crept up a while ago, and surely we don't rely on Bobo Balde this much?
Playing John Hartson was like playing with a man down today, let's see if Gordon Strachan has the balls to drop him next week.
Only Artur Boruc and possibly Shaun Maloney receive pass marks for today, and the whole team need to give themselves a shake. Maybe today's shock result will be the wake-up call the team needed.
These assessments are not purely based on today, but half a season. We need at least three quality defenders bought this month. We're lucky to be so far ahead of Rangers or we would be in serious danger of throwing the SPL title away again!