Pep Guardiola's side secured a narrow victory in this rescheduled match just outside town, and take a slender advantage into the return at Camp Nou before Christmas
Barca made the short trip to Hospitalet, just outside the Catalan capital, in a game rescheduled due to the European champions' participation in the Club World Cup in December.
With a return at Camp Nou coming just three days after the final in Japan, coach Pep Guardiola stressed the importance of taking an advantage into that match against the Segunda Division B side.
His cause was not helped by the loss of several of his stars due to this week's international matches, with Lionel Messi, Alexis Sanchez, Dani Alves and Adriano all away with their South American national sides.
However, Barca's Spain's stars were given special dispensation to start in this match ahead of the friendly against England at Wembley on Saturday.
Carles Puyol, Xavi, Cesc Fabregas, David Villa and Iniesta all started, and it was the latter who gave Barca the breakthrough as he blasted home a lovely effort from outside the box two minutes before the half-time interval.
Before that, Villa - who has hardly featured for the Catalans of late - had a decent effort on target early on and Seydou Keita twice threatened for the visitors.
The Spain midfielder was replaced by Sergio Busquets after 62 minutes and moments later, another international team-mate, Cesc Fabregas, failed to convert after he was set up beautifully by Keita.
Barca were still dominating and Villa forced Hospitalet goalkeeper Jose Sanchez Moragon into a fine save from a free-kick after 76 minutes, moments after young Rafinha had come on to make his debut in place of Fabregas.
At the other end, though, Jose Pinto was called into action to deny Aday Benitez.
The visitors finished on top, however, and Villa was again thwarted by Moragon right at the end as Barcelona secured a narrow victory ahead of the return leg, which will be played four days before Christmas.
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