Jordi Alba helped Barcelona to extend Girona's run without a win in all competitions to 10 matches but insists their Catalan neighbours are one of the toughest opponents in LaLiga.
Nelson Semedo's first goal in Spain's top flight gave Barca a swift start as they sought to restore a five-point lead over Atletico Madrid at the summit, but Ernesto Valverde's men were far from their fluent best and had to wait for Lionel Messi to seal a 2-0 win in the 68th-minute.
Bernardo Espinosa's red card early in the second half had not been enough to derail Girona's challenge, with Marc-Andre ter Stegen making a trio of saves to frustrate Cristhian Stuani.