PSG and Barcelona have been in this situation before, and while the circumstances surrounding the second leg are different this time around, there's still plenty of intrigue to see if Barça can pull off the unthinkable again.
Nearly four years to the day of its comeback from a 4-0 first-leg deficit in the Champions League round of 16 vs. PSG, Barcelona heads to the Parc des Princes looking to overturn a 4-1 deficit. "La Remontada," as the 6-1 second-leg win in 2017 became known, featured a packed Camp Nou and an influential Neymar that helped Barcelona stun a shellshocked PSG.