The Argentinian wasted the chance to put the visitors in front after Carlos Puyol had cancelled out Jonas' opener for the hosts.
The visitors rode their luck in the first half, though, and might have had goalkeeper Jose Manuel Pinto sent off inside 20 minutes when a clear handball outside the area went unspotted by the officials.
Barca coach Pep Guardiola remarked afterwards: "It was the best game we've played here.
"They created the least amount of chances, beyond the stats we once again played very well on a very dry pitch and that's always hard. But they are coming and we'll wet the pitch down (at the Camp Nou)."