Kylian Mbappe fired home to open the scoring but his goal was cancelled out by Leonardo Bonucci’s equaliser before the break in a tight encounter in Turin on Wednesday.
PSG looked to have secured progress to the last 16 as group winners, though, when Mendes changed the picture midway through the second half.
However, a remarkable result for Benfica against Maccabi Haifa saw the Portuguese side score the six goals they required to pull level on goal difference with PSG and snatch top spot courtesy of away goals scored.
PSG’s quality showed after 20 minutes when Mbappe latched onto Lionel Messi’s pass, nutmegged Frederico Gatti and drilled in off the right-hand post for his seventh Champions League goal of the season.
Yet PSG were pegged back five minutes before the break – Bonucci sliding in to meet Juan Cuadrado’s diving header and convert from close range.
Chances continued to be hard to come by for both teams after the restart until the 69th minute, when Mbappe fed through substitute Mendes, who finished crisply across Wojciech Szczesny.
Manuel Locatelli saw a goal correctly disallowed for offside and Federico Chiesa – making his long-awaited return from injury as a substitute – had a penalty appeal waved away as Juve’s comeback attempts proved fruitless.
Juve were at least saved the embarrassment of an exit from European football entirely thanks to Benfica’s win in Israel, and the Bianconeri will fight for a place in the last 16 of the Europa League in the new year.
What does it mean? PSG fall short
Just under a year ago, PSG finished runners-up in their group and drew Real Madrid in the round of 16. After a 1-0 win in the first leg, a swift hat-trick from Karim Benzema in a 3-1 loss turned the tide and resulted in a dramatic and premature exit in March – one that all but sealed Mauricio Pochettino’s fate.
That prize fell to Benfica, however, with PSG fans having to worry about a potential match against the likes of Madrid, Bayern Munich, Liverpool or Manchester City.
Messi and Mbappe magical
In truth, with PSG’s attack this Messi’s assist for Mbappe’s opening goal was his eighth goal involvement in five Champions League appearances this season (four goals, four assists), the first time he has more than three assists from the group stages of the competition.
Mbappe stands top-scorer in the competition with seven, alongside Liverpool’s Mohamed Salah, with a goal and assist against Juve taking his tally in the past three matches to four goals and three assists.
Juve’s unwanted record
A fifth loss in the Champions League for Juventus this season was only the second time they have lost so many times in a single campaign, having previously lost five in 2002-03 – though that came with one defeat in the first group stage, three in the second and one in the semi-final.
Juventus also became only the second Italian side to lose five matches in a single Champions League group stage, following Roma’s 2004-05 side (D1, L5).
PSG will look to maintain their unbeaten run across all competitions when they travel to Lorient in Ligue 1 on Sunday, while Juventus face a crucial Serie A test against Inter on the same day.