The 33-year-old set the milestone after tying club legend Xavi on 767 appearances in last week's 4-1 win over Huesca.
Messi is now the Blaugrana's all-time leader in games played, goals scored (663), assists (287), and titles won (34).
Messi, who's starred for the club since making his first-team debut in 2004, has exploded into form, racking up 16 goals and seven assists in his last 12 matches.
The good vibes continued Sunday with another monumental victory that keeps Barcelona in the La Liga title race. The Spanish giants are four points behind Atletico Madrid with 10 games remaining.
Though Messi's future at Barcelona remains unclear, there's hope he'll renew his contract before it expires at the end of June. Despite facing mounting debt, newly elected club president Joan Laporta has vowed to do everything he can to keep Messi, who nearly left Barcelona last summer, citing differences with then-president Josep Maria Bartomeu.