Captain Gerard Pique gave them a 19th minute lead with Martin Braithwaite finding the net in first half injury time and in the 59th minute. Sergi Roberto added a fourth in the last minute of the game.
Just over 20,000 fans were in attendance as crowds returned for the first time since the pandemic.
Six-time Ballon d'Or winner Messi called time on his two-decade career at Barcelona last week and moved to Paris Saint-Germain.
