Chasing an incredible four-goal comeback in Camp Nou, Barcelona were 2-0 up when Neymar was brought down in the area.
After consulting with the official behind the goal, referee Deniz Aytekin eventually gave the spot-kick in the Catalans' favour, and Messi made no mistake in drilling home to Kevin Trapp's right-hand side.
And in doing so, the Argentine drew level with his eternal Real Madrid rival in Champions League spot-kicks.
11 - Lionel Messi has equaled Cristiano Ronaldo as the player with most penalties scored in #UCL history. Remuntada.— OptaJose (@OptaJose) 8 de marzo de 2017
Messi has now scored 11 times from 12 yards in the European competition, the highest of any player in competition history alongside Ronaldo.
In converting against PSG, he also marked his 37th knockout goal - a figure that puts him behind only Ronaldo.
37 - Lionel Messi has scored his 37th Champions League goal in the knockout stages; only Cristiano Ronaldo has more (44). Special.— OptaJoe (@OptaJoe) 8 de marzo de 2017
The goal put Barcelona 3-0 ahead, although Edinson Cavani pulled one back to necessitate at least three more home goals for the Catalans to go through.