The outcome of this first leg before a crowd of 75,532 was determined by two goals in three minutes in the first half when Edin Dzeko’s superb volley and Henrikh Mkhitaryan’s well-taken second put Inter, the "away" side in control, giving them a vital edge for next week’s "home" leg.

It is a unique situation as no other major city has one stadium shared by two top-level clubs. It doesn’t happen in Manchester where United play at the "Theatre of Dreams" Old Trafford, with big-money rivals City sweeping all before them at the Etihad, named after the airline of the country which owns them.

It doesn’t happen in Madrid where Real play in the temple that is the Bernabéu, while city rivals Atlético have recently moved into the functional, but unspectacular, Metropolitano Stadium.

It certainly doesn’t happen in Glasgow, where fierce rivals Celtic and Rangers are, like the city, divided along historical religious lines and would no more consider sharing a stadium than the two sets of fans would consider sharing a pub.

In Milan, though, the city’s clubs have been happily (mostly) sharing the San Siro since 1947 when Inter, who used to play in the Arena Civica downtown, became tenants. It is increasingly looking likely, however, that the two clubs are set to go their own separate ways with the future of the San Siro left in severe doubt when their current tenancy agreement officially ends in 2030.

The stadium is approaching 100 years since its construction in 1925, a period during which it has hosted games at the 1934 and 1990 FIFA World Cups, four European Cup finals and three 1980 European Championship fixtures.

The crux of the argument is that to continue to be able to compete at the very highest levels of European football, both Milan and Inter need to increase the amount of money they can generate, which neither of them believe is possible at the San Siro in its current configuration.

Like, most of the stadiums in Italy, the San Siro is owned by the city and the clubs pay rent to play there. That means they cannot make as much in revenue as other clubs around Europe that own their respective stadium and can't also invest as much as they want to renovate the infrastructure.

For example, English Premier League club Tottenham Hotspur, who recently moved into a new stadium in London, generate €125 million (£109 million/$136 million) per season in match day revenue, four times more than AC Milan.

San Siro saw few major renovations in 1937, 1954, 1990 and 2015, but even if it's still one of the most incredible and astonishing stadiums around the world, it can't compete with other ones in terms of revenue. 

Both Inter and AC Milan's first idea was to keep and renovate San Siro, but it is looking increasingly unlikely, meaning both clubs are now seriously investigating building their own stadiums in different areas of the city. If that happens, it will surely spell the end for a stadium called the "scala" of football.

"The first tier was built in 1926, the second in 1956 and a third added in 1990 with the roof," Inter chief executive Alessandro Antonello said. 

"These were placed one on top of the other but have very little connection between them. This means there are very limited spaces for businesses and restoration."

A project was approved in December 2021 when Inter and AC Milan announced, "The Cathedral" had been selected for their new stadium, which would also have led to the creation of a new district dedicated to sport and leisure, incorporating 110,000 square metres of green space and would be the first 'net-zero carbon arena in the world’. 

The area around the San Siro desperately needs some kind of boost as, besides the stadium, there is nothing - no cafés, no shops, no restaurants. It is completely barren.

Discussions have stalled since that original proposal and many things changed in the past year, which now appear to have scuppered their project.

Milan was sold to New York private investment firm RedBird Capital Partners, who consider the stadium a priority.

Inter, meanwhile, are facing an uncertain financial situation under Chinese owner Steven Zhang, who is facing allegations in Hong Kong of unpaid multi-million-dollar debts.

A crucial meeting is scheduled tomorrow between the two football clubs and Milan’s Mayor Giuseppe Sala after which, everything could change again.

The only thing which seems certain is that no renovations will be carried out at the San Siro before February 6, 2026 - the date it is due to host the Opening Ceremony of the Winter Olympic Games.

Giovanni Malagò, the President of Milan Cortina 2026 and the Italian National Olympic Committee has so far managed to steer a diplomatic course on the contentious issue. 

"At San Siro we are interested and attentive spectators, but it is a match that concerns the municipal administration and the two teams, it is not right for us to express a concept," he told the Italian media on the eve of the box office Champions League semi-final.

"We would like to reiterate what we have strongly wanted from day one, also for its capacity, its history and its importance, namely that the Opening Ceremony of the 2026 Olympics be at San Siro."

In the glorious history of the San Siro, it is increasingly looking likely that the Olympic Games will be the closing chapter.