ROBERTO MANCINI, the head coach of Internazionale, believes a stadium has the power to change a game.

He believes the electricity created by the crowd, packed in cheek-by-jowl in support of a common cause, can play a significant role in altering the flow of events. He believes that is what happened at Parkhead last week as his side gave up an early two-goal lead to draw 3-3 in the first leg of their tie with Celtic in the last 32 of the Europa League.

"In Glasgow, we started so well that the game seemed almost too easy," said Mancini. "After a while, we got lax with our marking, but, in these arenas, the results can change in a minute.

"They just needed one goal to become extraordinary thanks to the passion of the fans."

The atmosphere will be nowhere near as thunderous for the return on Thursday. San Siro remains one of the iconic venues in world football, but has become an unloved relic of a bygone era.

Capable of holding 85,000 people, it is normally to be found only half-full. Inter's last home fixture, a 3-0 win over Palermo, for example, attracted a mere 30,085 spectators. The Celtic manager, Ronny Deila, visiting on a spying mission, made mention of how quiet it was.

If anything, particularly given the miserable form of Inter and their rivals AC Milan this season, it is easy to suggest that the negativity surrounding San Siro these days is draining the life from the players rather than providing the energy that was almost tangible in the east end of Glasgow when John Guidetti scored that last-gasp equaliser.

AC Milan have already decided they have had enough. They have made plans for a 48,000-seater ground in the Portello area of the city and are expected to move out in 2018.

Inter are in talks with the local authorities about staying put, either in their current role as tenants or perhaps as outright owners, but their president, Erick Thohir, is understood to be considering removing the top tier and reducing the capacity to 56,000.

Major improvements are needed. The ground looks tired, but the problem is that both clubs and the local council have to make an equal contribution to the refurbishment work.

Massimo Moratti was widely reported to be keen on moving Inter to a 60,000 capacity venue in San Donato prior to selling his controlling share to Thohir in October 2013. He clearly believes they have to get out of San Siro with Juventus, who left the cavernous Stadio delle Alpi in Turin to move to a custom-built 41,254-seater ground in 2011, reaping the benefits of downsizing.

"Italian football's downfall is related to decisions made within the country," said Moratti. "San Siro is a magnificent stadium, but does not make Milan clubs the money that it could.

"Stadiums such as San Siro are also too big. In a smaller stadium, fans fear not getting a good seat and season ticket subscriptions would then go back up."

Moratti has a bleak view of where Inter and Italian football stand right now. Juventus are the only Serie A club to have reached the last 16 of the Champions League, while four of the five teams left in the Europa League failed to win their first leg matches.

"It will take time to get back," said Moratti. "Today, Italian football is in pretty bad shape.

"I'm no expert, but the Milan clubs returning to the pinnacle of European football will take years, in my opinion. There is a huge gap compared to clubs such as Bayern Munich, Manchester United or Real Madrid."

Meanwhile, Inter's captain, Andrea Ranocchia, may miss Thursday's visit of Celtic as a result of a persistent knee problem.

"He's doing everything possible to play," said Mancini.