Given their healthy 2-0 lead from the first leg, Inter needed only to remain tight defensively and patiently wait for their moment to pounce in order to see the job out.
And that approach worked perfectly as the quarter-hour mark loomed, when Nicolo Barella – also the opening scorer at the Estadio da Luz a week ago – cut inside Antonio Silva and Chiquinho before curling a divine effort into the top corner.
Inter could have truly blazed out of sight soon after when Odysseas Vlachodimos dropped Federico Dimarco’s cross, but the goalkeeper recovered to claw the ball away from Edin Dzeko.
Contrastingly, Benfica were largely starved of opportunities in the opening half-hour, with Alex Grimaldo’s dipping free-kick being well dealt with by Andre Onana.
However, a chink in I Nerazzurri’s armour was exposed by Rafa Silva’s cross in the 38th minute. Fredrik Aursnes, whose only other goal for As Aguias had come at Santa Clara’s 13,277-capacity Estadio de Sao Miguel, capitalised on lax defending to head in an equaliser and stun the San Siro, while offering the Primeira Liga leaders some faint hope of mounting a miracle comeback in the tie.
Undeterred, Martinez showed Inter’s intent after the restart with a strike that curled agonisingly wide, before then blocking an attempted clearance from Vlachodimos.
While Benfica had moments of promise, there was no stopping their hosts when Martinez’s intensity and guile was matched by Dimarco.
The wing-back got behind Aursnes to set up the Argentine in the 65th minute, and he ended a run of eight goalless matches with a clinical first-time finish, sending the Inter faithful into unbridled euphoria.
Adding extra gloss to a sensational evening mere minutes after being introduced from the bench, Joaquin Correa beat Nicolas Otamendi with a drop of the shoulder and Vlachodimos with an exquisite strike that crashed in off the post.
Despite Silva scoring a late header and Petar Musa following it up with an instinctive finish in the final seconds, Inter fans simply partied in the dying moments, with a tie against AC Milan in the semi-final confirmed.
Flashscore Man of the Match: Lautaro Martinez (Inter Milan)
