Messi voted Barcelona captain as Koeman's team win first friendly
Barcelona beat the third-tier side 3-1 with goals from Ousmane Dembele, Antoine Griezmann and Philippe Coutinho.
Messi made his first appearance of the season after being confirmed as Barcelona captain for the campaign.
Team-mates voted the Argentinian as the dressing room leader despite his attempts to move away in recent weeks. He opted to stay in the end.
"Messi's quality speaks for itself," said coach Ronald Koeman. "He knows he has to get fitter before the start of the season."