Glasgow, it seems, has recaptured its old image. Visitors have a sense of trepidation, though it has nothing to do with the violence which once blighted the city.
The razor gangs of the 1930s earned Glasgow the description of No Mean City, after the book of the same name, but in football terms it is now the meanest city in Europe.
Parkhead and Ibrox have become places where others fear to tread. Celtic's midweek Champions' League defeat of Lyon means that only once in Martin O'Neill's three years in charge has his team lost a European tie at home - and that was to Ajax in 2001, when Celtic had already killed off the tie with a 3-1 success in Amsterdam.
Rangers are equally entrenched at Ibrox. It is now 15 games since they lost a European game there. Next up, Manchester United, who may not feel quite so comfortable about this fixture as they were when the draw was made a month ago, now that Alex McLeish's side lead Group E.
However, Celtic went to Ibrox last April, fresh from reaching the Uefa Cup final, and inflicted a 2-1 defeat upon their Old Firm rivals that helped to take the Scottish Premier League title duel right down to the wire on the last day, before McLeish's team snatched the championship with a goal difference of one.
That narrowest of failures to hold on to the Scottish title still causes rancour in the Celtic camp. Chris Sutton is only just back from a five-game domestic suspension imposed after he accused Dunfermline - who lost 6-1 at Ibrox on the final day - of lying down to Celtic's rivals, but the goal he scored against Lyon has heightened the campaign to have the former Blackburn Rovers and Chelsea forward return to the England set-up.
Sven-Goran Eriksson can save himself the plane fare today, given that the match is live, yet again on the BBC, and broadcast to the rest of Britain.
Last season, the pair served up 11 goals in the first two league games, before they toned it down a bit and Celtic secured a 1-0 win at Parkhead to go with their later success at Ibrox.
"Usually, the team that wins the first derby is supposed, by tradition, to go on and win the league," said McLeish yesterday.
"The first one last season finished 3-3 and then we won the next. However, Celtic then took the last two and had a better head-to-head record against us - yet we still won the title.
"So it is not just down to this one fixture - though it is a very important one," he said.
McLeish, whisper it down Govan way, has a lot of time for Celtic. But that will just make him want to win this encounter all the more.
He believes the Old Firm's impressive Champions' League start has "raised the reputation of Scottish football this season." He is, however, piqued at being made to play at lunchtime today when his squad only stepped off the plane from Athens 55 hours earlier after a draining night when a last-minute goal robbed his team of a deserved success away to Panathinaikos.
"We asked about having the game changed to a Sunday once we knew the Champions' League draw, but we were told that could not happen. It's all down to television. However, Celtic proved last season that it was not an obstacle when they came back from Portugal and beat us.
"Celtic's achievements last season in getting to the Uefa Cup final put them on the European map and they showed that again by beating Lyon.
"Their profile has been raised. However, so has ours. For us to win the title last season, showed what an achievement that was.
"Some people show disrespect to Scottish football, but we edged out a Celtic side that is very good one."
O'Neill, whose team are two points behind after seven games, was dripping with as much magnanimity yesterday. He believes that Rangers are as good as they were last season, despite the departure of Barry Ferguson to Blackburn Rovers.
"Rangers have changed some personnel, but the way they play is still the same," said O'Neill.
"They have a lot of confidence, which has been shown in their results and in many respects they are as good as they were last season.
"Rangers at Ibrox represents a formidable task for us. It will be a hard one, but after Tuesday we will go there with plenty of confidence."
The Celtic manager even empathised with McLeish over the timing of the encounter.
"From last season, circumstances have changed. These fixtures were arranged before we even knew that we would be in the Champions' League, but I have absolute sympathy for them," he said.Reuse content