However Barcelona went ahead after 25 minutes when Oriol Romeu fed Félix.
The on-loan Atletico forward controlled the ball, slipped it past goalkeeper Rui Silva and then clinically fired the ball into the goal from a tight angle.
“I’m very happy to start again, the emotions are great – it’s easy to play in this team,” Felix told Movistar.
Felix, signed by Atletico Madrid for a club record fee of €126 million ($134 million) in 2019, failed to find consistent form in the capital and was loaned to Chelsea last season.
“I am happy, the change has benefited me and my family, I am very happy here,” he said.
Lewandowski doubled Barcelona’s lead when he ran onto Andreas Christensen’s pass and fired home the goal, but the goal was saved by Félix, whose clever dummy allowed the ball to find the Polish striker.