Trezeguet grabbed Villa’s stoppage-time winner to send the five-time victors to Wembley after Kelechi Iheanacho’s second-half strike had cancelled out Matt Targett’s 12th-minute opener to give Villa a 3-2 triumph on aggregate.
Villa, though, owe a huge debt of gratitude to goalkeeper Orjan Nyland, who produced three outstanding first-half saves, with boss Dean Smith opting to keep faith with the Norwegian who had served him well in the first leg at the King Power Stadium, at the expense of recent signing Pepe Reina.
The opening 10 minutes belonged to Leicester, and Nyland in particular.
An early chest block from an acute angle to deny Iheanacho, starting with leading scorer Jamie Vardy on the bench after sustaining a glute injury in last Wednesday’s 4-1 hammering of West Ham, was routine, but what followed was sublime.
A fifth-minute lay-off from Iheanacho for James Maddison resulted in a low right-footed curler that was bound for the bottom corner, only for Nyland to tip the ball beyond his left-hand post.
After Maddison had then drilled a first-time drive from just outside the area inches past the same section of the goal frame two minutes later, the midfielder was again brilliantly thwarted by a full-stretch Nyland’s fingertips in the ninth minute.
What followed in the 12th from Villa was a good old-fashioned counter-punch as breaking from deep, Douglas Luiz fed Jack Grealish down the left, and after a surge into the box, the Villa skipper in turn played in the overlapping Targett.
In front of the Holte End, the defender then struck a sweet first-time drive from an acute angle beyond Kasper Schmeichel for only his second goal since his £15.6million move from Southampton in the summer.
Villa were inches away from making it 2-0 in the 15th minute, with Anwar El Ghazi curling a 25-yard free-kick fractionally over the bar after Maddison had brought down Grealish.
The goal naturally changed the momentum of the game, settling Villa, although Nyland’s best in the first half was yet to come.
Letting fly from 20 yards, Youri Tielemans’ curling strike was destined for the top corner, yet with a clawing right hand, Nyland managed to push the ball on to the bar, with a replay drawing gasps and applause from the home fans.
Shortly after, though, City should have been awarded a penalty, but despite a VAR check, the officials at Stockley Park failed to spot Marvelous Nakamba’s block to another effort from Maddison.
After Grealish had fired wide from 12 yards in the 54th minute, and Vardy was thrown on by Rodgers two minutes later to find the elusive equaliser, Villa should have put the tie beyond City’s reach just after the hour.
But despite a piercing delivery to the edge of the six-yard box from Grealish, new £8.5million signing Mbwana Samatta failed to get the necessary touch that would have made him an instant hero on his debut.
It proved costly as 18 minutes from time Iheanacho, who had scored City’s equaliser in the first leg, repeated the trick by arriving at the far post on to Harvey Barnes’ threaded ball through the six-yard box to the far post for his sixth goal in five games against Villa.
After Foxes centre-back Jonny Evans had spurned a headed chance four minutes from time, Villa then grabbed the winner in added time as two subs combined, with Ahmed Elmohamady’s deep ball to the far post from the right wing met by the arriving Trezeguet to plant his shot back across Schmeichel.
Aston Villa reached their first league cup final for a decade with a dramatic 2-1 victory over Leicester in the second leg of their semi-final at Villa Park.