Martinez fired the only goal of a stop-start second leg to add to their 2-0 victory in last week’s opening instalment and Inter will face either Manchester City or Real Madrid in Istanbul on 11 June (AEST).

Argentina’s FIFA World Cup winning-striker, who was outstanding throughout, pounced in the 75th minute as Inter clinched an eighth successive win in front of a crowd of 76,000 at the San Siro.

It secures its first Champions League final since 2010 – when Jose Mourinho masterminded the treble before leaving to join Real Madrid – and keeps alive hopes of lifting a fourth European crown.

Aware of the need for urgency in the 237th derby between the city rivals, Milan started fast and in the 14th minute it was presented with a chance to blow the tie wide open.

Sandro Tonali skilfully created the space for Brahim Diaz to have a clear shot at goal but the Spain forward’s attempt lacked conviction and keeper Andre Onana made a simple save.

Rafael Leao flashed a shot across the face of goal and if Milan were taking heart from their opportunities, that was offset by Inter’s own threat with Martinez going close on two occasions.

On the second of those only a stunning reflex save by Mike Maignan kept out a dangerous header to keep Milan in the hunt.

The importance of Milan’s missed chances was underlined when the second half opened with Inter taking charge of the ball, frustrating opponents who appeared to have run out of ideas.

A sly off-the-ball stamp by Francesco Acerbi on the foot of Tonali incensed Milan’s players but referee Clement Turpin declined to act.

Inter’s position was beginning to look unassailable and shortly after Romelu Lukaku stepped off the bench, the Belgian combined with Martinez to confirm their place in the final.

Lukaku held the ball up in the corner of the area and when the right moment came, he threaded a pass to his team-mate who produced a fine first touch before beating Maignan at the near post.

Martinez’s moment of brilliance was a rare highlight of a second half that became increasingly niggly, resulting in a spate of yellow cards, and Milan had nothing left to offer.