Rangers may have clinched the Scottish Premier League championship, but there were no winners, only losers. Celtic lost, Glasgow lost, the Old Firm lost, and, most importantly, football lost.
Celtic paid the heaviest price. Gone was not only their title, but also their pride. A club whose supporters have nurtured such a reputation for good behaviour that they are overwhelmed with offers from England to play testimonial matches, simply could not turn the other cheek when faced with the prospect of surrendering their crown to their bitter rivals on their own ground.
The four fans who tried to invade the pitch to attack the referee, Hugh Dallas, have already been banned for life by the club and face criminal charges, while close circuit television is being studied in the hope of identifying the culprit whose missile inflicted a head wound on Dallas.
Such numbers are a drop in the ocean when set against the 53,000 other Celtic season ticket holders who did not break the law, but after Dallas had been hit and then awarded the penalty with which Jorg Albertz gave Rangers a 2-0 lead, there was a dark period when the tide of hate sweeping down from Celtic Park's huge stands threatened to engulf the evening. The players must take a long, hard look at their actions in that period. Other matches may be able to contain three sendings-off and 10 bookings, but in an Old Firm game such indiscipline sends out ripples that provoke waves of trouble far from the pitch.
More than 100 arrests were made in Glasgow on Sunday night as fans fought in streets near Parkhead and rival bars were attacked. The police riot gear was not an overreaction, with more than 100 officers coming under attack from 150 Rangers fans in one incident.
"Disgrace" declared the Daily Record headline, while the Sun's front page screamed "Bloody Mad." Its back page headline was more apt in its summing up of the occasion: "90 minutes of pure poison!"
Glasgow has seen it all before. For 110 years this tribal mixture of football and religion has spilled on to its streets. The world, however, had not seen the Old Firm at its worst. Until Sunday night.
Television coverage of the match was beamed via satellite to more than 120 countries, and it hardly presented a pretty picture. The former Celtic and Arsenal player, Charlie Nicholas, who is now a Sky commentator, could only shake his head and say: "For the first time in my life, I felt ashamed to be a Celtic fan. I have never seen an Old Firm fixture plumb such depths and I can't begin to tell you how embarrassed I am."
The players from many nations who made up the two sides did not seem to appreciate that their actions carry consequences on the streets. Nicholas grew up on those streets and knows that the hostility needs no foreign aid. The three men sent off on Sunday - the Frenchman Stephane Mahe, the Norwegian Vidar Riseth and the Englishman Rod Wallace - betrayed little appreciation that their behaviour could have a direct effect on the crowd. Mahe, in particular, could be said to have sparked the subsequent trouble for Dallas. It was three minutes before Mahe could be persuaded to leave the field, after he fought against the efforts of his team-mates and club staff who tried to pacify him. It was his second sending-off in an Old Firm game. The Italians Sergio Porrini of Rangers and Celtic's Enrico Annoni also threw punches at each other when Wallace's dismissal threatened to spark a mass brawl.
Such behaviour is not acceptable in a place less than half a mile from where a teenage Celtic fan was stabbed to death four years ago simply for walking through the wrong area.
The last decade has seen a dilution of local knowledge among the Old Firm players, but sadly the evidence is that the newcomers offer little in the way of a cosmopolitan influence. In 1997, Paolo Di Canio was sent off amid gestures of reprisal; in 1991, Rangers finished with eight men in one derby after the English trio Mark Hateley, Terry Hurlock and Mark Walters were dismissed. The Scottish courts do not view such incidents lightly. Terry Butcher and Chris Woods, then England internationals, were fined for breach of the peace in 1987 for a punch-up that also involved Frank McAvennie.
The Rangers coach, Dick Advocaat, was fined pounds 1,000 last month for a tirade against a referee that was not unlike Mahe's and some of his antics around the dug-out this season have been an embarrassment.