(CNN) -- What a difference a Messi makes. Last weekend "King Leo" inspired Barcelona to a seven-goal victory on the opening day of the Spanish soccer season, but in his absence Sunday the reigning champions battled to beat Malaga 1-0.
With the four-time world player of the year rested after suffering a bruised thigh in the midweek Spanish Super Cup draw with Atletico Madrid, new coach Gerardo Martino stuck to his word and left $75 million signing Neymar on the substitutes' bench.
And without a recognized striker, Barca struggled to make the team's usual dominance of possession pay off -- the winner at Malaga came courtesy of a superb curling shot by defender Adriano from outside the penalty area.
Neymar did get another run, but the 21-year-old Brazil star was unable to repeat his goal against Atletico as he was subjected to a series of rough challenges -- and had a late free-kick well-saved.
Earlier, Xavi's free-kick was deflected against the Malaga crossbar, but Barca ultimately had keeper Victor Valdes to thank -- as well as the woodwork.
Fabrice Olinga scrambled a shot that rebounded to safety off the post, then Sebastian Fernandez headed straight at Valdes when he should have equalized.
The win left Barca top of the table on goal difference from Atletico, despite the Madrid side's 5-0 thrashing of Rayo Vallecano earlier Sunday.
Raul Garcia scored in each half while Diego Costa, Arda Turan and Tiago also netted in a perfect warm-up for Wednesday's trip to the Nou Camp for the second leg of the Super Cup.
Real Madrid can also move onto six points by beating Granada on Monday, ahead of the expected unveiling of Tottenham forward Gareth Bale in what is tipped to be a world-record transfer fee.
Levante recovered from last week's drubbing by Barca, holding Sevilla 0-0, while Real Betis Celta Vigo beat Real Betis 2-1 in Sunday's late match despite having Borja Oubina sent off near the end.
In Italy, Inter Milan beat Genoa 2-0 in Walter Mazzarri's first match in charge, with Japanese defender Yuto Nagatomo and Argentina forward Rodrigo Palacio scoring in the final 20 minutes.
"We must remember that these lads had gone four and a half months without winning at home, and there were lots of defeats in there too," former Napoli coach Mazzarri said, referring to the disastrous form which left Inter ninth in the table last season and well short of European qualification.
"We needed to shake off this fear that we'd concede on the first counter-attack. The players just needed a bit of belief."
Napoli's new coach Rafael Benitez also had a winning start as last season's runners-up beat Bologna 3-0, with two goals from Slovakian playmaker Marek Hamsik and the opener from former Real Madrid forward Jose Maria Callejon.
French coach Rudy Garcia was similarly successful in his first match with Roma, coming away from promoted Livorno with a 2-0 win thanks to second-half goals from Daniele De Rossi and Alessandro Florenzi.
Lazio, fifth in the previous campaign, bounced back from last weekend's 4-0 Italian Super Cup defeat by Juventus to beat Udinese 2-1.
In France, champions Paris Saint-Germain won for the first time this season, beating Nantes 2-1 following two earlier draws.
Edinson Cavani, an $84 million signing from Napoli, put PSG ahead in the first half before an own-goal by defender Alex, but Ezequiel Lavezzi pounced for a 74th-minute winner after Lucas' shot was blocked on the line.
The result left Laurent Blanc's team four points behind top side Marseille and two behind second-placed Monaco.
In Germany, Eintracht Frankfurt notched a first win this season, 2-0 at Eintracht Braunschweig which left the promoted side bottom of the table without a point.
Stuttgart's 2-1 defeat by Augsburg left the five-time Bundesliga champions also on three losses.