Félix got a loud ovation from the Barcelona fans as he was substituted in the 68th.
The five-time European champions are not playing at Camp Nou this season while the venue undergoes renovation work.
Barcelona have not reached the knockout round of the Champions League since Lionel Messi left the club in 2021. Before that, they had made it through the group stage every year since 2001-02.
Earlier, AC Milan were held at San Siro in a hard-fought contest by a Newcastle United side returning to the Champions League after a two-decade absence.
Milan’s Portugal winger Rafael Leao, who has scored in his last two games, was a constant threat down the left and kept the Newcastle defence busy but was let down by his finishing.
“We’re disappointed, because when you play like this, you have to win,” Milan manager Stefano Pioli said.
“The performance was all-round good, but we wanted to win. Our aim is to progress from this group and we wanted to start well. We didn’t take easy chances.”
Julian Alvarez celebrates one of his two goals for holders Manchester City.Credit: Getty
Last year’s Champions League semi-finalists enjoyed a dominant opening spell and tested Newcastle goalkeeper Nick Pope with long-range efforts from Tommaso Pobega and Leao before Samuel Chukwueze had a header saved.
The best opportunity of the first half fell to Leao in the 34th minute but the 24-year-old miscued an elaborate backheel after skipping past two defenders in the penalty area.
Though Newcastle defended better after the break, Milan continued to press in their search for an opener.
Half-time substitute Alessandro Florenzi found Leao with an inch-perfect cross in the 74th minute, but the Portuguese again failed to find the target as he put his header over the bar.
Milan, who ended the night with a tally of 25 shots, were also dealt a double injury blow with midfielder Ruben Loftus-Cheek and keeper Mike Maignan having to be substituted.
At the other end of the pitch, the visitors’ efforts were limited to counterattacks.
Eddie Howe’s team had one attempt on target, which came when Sean Longstaff forced substitute keeper Marco Sportiello into a save with a shot from the edge of the area in the 95th minute.