The Argentine guided the Spanish champions to a nervy 1-0 win at home to Granada in La Liga on Sunday, in Quique Setien’s first game in charge of the club.
Messi struck the only goal in the 76th minute, firing into the bottom corner to complete a well-crafted team move, shortly after the visitors had defender German Sanchez sent off.
The victory puts Barca back to the top of La Liga on 43 points after 20 games, ahead of second-placed Real Madrid on goal difference.
Barca, who sacked Ernesto Valverde last week despite being La Liga leaders and winning the last two titles by considerable margins, enjoyed 82% of possession and made a staggering 1005 passes in their first game under Setien.
The former Real Betis coach is known for his devotion to the possession-based style of play Barca became renowned for under Johan Cruyff and which they perfected under Pep Guardiola.
Granada, however, proved to be stubborn opponents, beating Barca 2-0 in September.
The visitors even came close to taking the lead when Cameroonian Yan Brice Eteki struck the post in a rare foray forward, but they eventually caved in after Sanchez picked up a second yellow card and was dismissed for hauling down Messi.
Messi had come closest to scoring for Barca with two powerful yet inaccurate shots either side of halftime, but he made no mistake when Arturo Vidal dragged the ball into his path in a slick passing move engineered by substitute Riqui Puig.
Twenty-year-old Puig was rarely given a look in by Valverde but he was given his first league appearance of the season by 61-year-old Setien, who has pledged to honour the club’s tradition of giving young, home-grown players a chance.