Roy Keane's Celtic debut ended in a humiliating defeat after his side were sent crashing out of the Tennent's Scottish Cup by Division One Clyde.

All the hype before the third round tie surrounded the arrival of the former Manchester United skipper onto the scene.

But the Bank of Scotland Premier League leaders slumped to one of the most embarrassing defeats in their history against a side who were only assembled by manager Graham Roberts after summer trials.

Craig Bryson and Eddie Malone put Keane in their shade with first-half goals but it could have been even worse for Celtic but for some key decisions by the officials and the saves of Artur Boruc.

The Hoops were a shambles in defence as Du Wei also endured a debut to forget as manager Gordon Strachan made three changes from the side which beat Hearts.

Keane endured a quiet start to his new career as Clyde came close to breaking the deadlock early on. Craig Bryson ran at the Celtic rearguard in the eighth minute and drove a right-foot shot over the crossbar from 20 yards.

Shunsuke Nakamura replied by sending Peter Cherrie scurrying frantically across his goalline as the Japanese star sent a left-foot free-kick past the far upright from 25 yards.

But Du Wei had a shaky opening and was fortunate not to gift Clyde a shock lead in the 15th minute in a moment of controversy.  He was caught off-guard as Tom Brighton raced on to the ball before coolly slotting the ball past Artur Boruc - only for referee Kenny Clark to penalise the striker for fouling the defender in the process.

The First Division side ignored that disappointment to go close again in the 23rd minute.  Steve Masterton had Boruc saving to his right to keep his right-foot effort from nestling in the top corner.

But moments later the Polish goalkeeper spilled the ball to cause panic in the Celtic goalmouth. Alex Williams rolled Eddie Malone's cross into the back of the net only for jubilation to turn to misery again.

This time the linesman had his flag up for offside but justice seemed to be done in the 33rd minute when Clyde deservedly took to lead.  Malone crossed for Bryson to fire past Boruc from six yards but it could have been much worse moments later.

Du Wei pulled down Brighton and the referee pointed to the spot - only for Boruc to fling himself right to save Stephen O'Donnell's effort.  But Clyde were in dreamland soon after when O'Donnell's 37th-minute corner skimmed the head of Du Wei and Maloney launched a left-foot volley into the top corner to make it 2-0.

Not surprisingly Strachan replaced Du Wei with Adam Virgo at the break but Celtic still continued to make mistakes.  Ross Wallace was the next defender to put his team-mates under pressure when O'Donnell accepted his loose pass.

The skipper sent Brighton away and he drove a powerful right-foot shot just over the crossbar from just inside the area.

Clyde looked like the Bank of Scotland Premier League side and they would have gone further ahead in the 53rd minute but for a brilliant save from Boruc.  The goalkeeper threw himself down to his left post to save O'Donnell's head from Bryson's centre.

Strachan made another change by bringing on Aiden McGeady for Wallace and he could have gave pulled the shell-shocked Parkhead man back into the game in the 63rd minute but he failed to even the target with Clyde keeper Cherrie to beat.

Strachan's last throw of the dice saw Maciej Zurawski introduced - and the Pole set-up a grandstand finish by hitting the back of the net with a low strike from inside the box with seven minutes remaining.

But the underdogs survived the late Celtic surge and rightly celebrated a famous and well-deserved victory at the final whistle.