Quique Setien won his first game as Barcelona boss as Messi scored the only goal to beat Granada 1-0 in La Liga on Sunday.
Although Barca had more than 80% of the possession, the La Liga giants were far from impressive as their build up was very slow.
Teenager Ansu Fati, who started in a front three with Messi and Griezmann, made two early efforts, one of which resulted in a superb save from Rui Silva.
Granada spent most of the match defending. And when German Sanchez was shown a red card for a foul on Messi in the 69th minute, it gave a much needed opening for the home side to strike seven minutes later.
Messi found the back of the net from Arturo Vidal’s backheel to send Barcelona to top of La Liga with just a goal difference above second placed top rivals, Real Madrid.
Setien celebrated after the goal and final whistle as he witnessed his first victory after replacing Ernesto Valverde as Barça head coach.
Barcelona’s next match is a Copa del Rey quarter-final match at Ibiza on Wednesday.