Milan and Inter have already met in the UCL knockouts on two prior occasions. In 2002/03 they met in the semi-final where Milan edged past Inter on the away-goals ruling. In the 2004/05 quarter-finals, Milan empathetically defeated their rivals 5-0 on aggregate. Those were the days of Marco Materazzi, Paolo Maldini, Filippo Inzaghi, and co.
The teams are not as star-studded in modern times, but there is still the chance for fresh history to be written. In Champions League bets, Inter Milan is the clear favorite to progress beyond their rivals offered at -138 to qualify for the final. However, the final would present a much bigger task for either side. In Champions League winner odds, Manchester City is the outright favorite at odds of -138. However, whoever wins the other semi-final tie between Real Madrid and City would enter the final as the heavy favorite. The Italians are huge underdogs, but they certainly do not lack European pedigree.
The two Milan sides have won the competition 10 times between them and are certainly not in unfamiliar territory. Both have endured difficult times in recent history. Serie A clubs generally lack the financial strength to compete in the transfer market with sides from La Liga and the Premier League. There is certainly not a level playing ground anymore, but in the past Italian teams ruled Europe.