The Argentine was back to his brilliant best with two goals in Luis Enrique's first game as coach of the Catalan club, while superb youngster El Haddadi added anotherLa Liga was back with a bang at the weekend as Spain's elite returned to Primera Division competition for the first time since the 2013-14 championship concluded in May.
Barcelona and Real Madrid made winning starts against Elche and Cordoba, respectively, but champions Atletico had to settle for a point following a goalless game at Rayo Vallecano. Elsewhere, there were wins for Malaga, Granada, Eibar, Celta Vigo and Villarreal on an exciting weekend of action.
Here, Goal takes a look at the standout performers from the opening round of La Liga.
In goal, Carlos Kameni was a surprise starter for Malaga ahead of summer signing Guillermo Ochoa and the Cameroonian pulled off a number of excellent saves to deny Athletic Club in a hard-fought 1-0 win.
At the back, defender Jean-Sylvain Babin marked his debut for Granada with the winner in a 2-1 victory over Deportivo La Coruna. Another debutant, Lucas Orban, rescued a point for 10-man Valencia at Sevilla as he chested home the leveller late on. Ex-Valencia defender Jeremy Mathieu makes up the back line after an accomplished first appearance for Barcelona.
In midfield, Almeria's Fernando Soriano is included after scoring in his side's 1-1 draw against Espanyol. He is joined by Eibar's Javi Lara, who netted the only goal of the game in his side's Liga debut against Real Sociedad. Meanwhile, winger Denis Cheryshev (on loan from Real Madrid) impressed and scored a late second for Villarreal in their 2-0 success at Levante, while Celta's Fabian Orellana was outstanding and netted a fine second in the Galicians' 3-1 win over Getafe.
In attack, Lionel Messi was back to his brilliant best for Barcelona with two goals in the 3-0 victory over Elche. Youngster Munir El Haddadi scored the other and was a big hit on his debut. Those two are joined by former Barca forward Nolito, now the star at Celta and scorer of the Galicians' first goal against Getafe.