Porto earned it.
The Portuguese visitors to Turin played 66 minutes with 10 men and overcame throwing away a two-goal aggregate lead to advance past Juventus on away goals after a 3-2 second-leg loss on Tuesday left the tie at 4-4.
Sergio Oliveira scored an early penalty and then put a 115th-minute free kick under a leaping Cristiano Ronaldo and the Juventus wall to make it 4-3 before Juventus set up a grandstand final few minutes of extra time via Adrien Rabiot.
Porto joins Borussia Dortmund as the first two 2020-21 UEFA Champions League quarterfinalists.
USMNT midfielder Weston McKennie entered in the 75th minute for Juve, winning five-of-six duels and taking three shots in 45 minutes but giving away a foul to an embellishing Oliveira after a hand on his shoulder.