A late goal that Timothy Weah set up for Arkadiusz Milik earned Juventus a spot in the Italian Cup final - keeping alive the Turin squad's chances of winning its first trophy in three years.
While Lazio won the second leg of their semifinal 2-1, Juventus advanced 3-2 on aggregate.
Weah sent in a cross seven minutes from time that Milik tapped in.
Taty Castellanos scored a goal in each half for Lazio.
Juventus won the first leg 2-0 with goals from Federico Chiesa and Dusan Vlahovic.
In the May 15 final back in Rome, Juventus will face either Atalanta or Fiorentina. Fiorentina takes a 1-0 advantage into the second leg of the other semifinal on Wednesday.
Juventus has won the Italian Cup a record 14 times, with its title in 2021 the most recent trophy the Bianconeri have claimed.
By reaching the final, Juventus also qualified for next season's four-team Italian Super Cup.
Castellanos is no stranger to coming up big in important matches, having scored four against Real Madrid last April while with Girona.
His first goal came 12 minutes in at the Stadio Olimpico when he leapt over Alex Sandro to head in a corner. Then shortly after the break, he muscled off Gleison Bremer to finish off a counterattack.
Juventus midfielder and United States international Weston McKennie limped off with an apparent left ankle issue after Castellanos' second goal but then came back on before eventually being substituted in
the 81st.
