The Argentine made his name as a midfielder at Liverpool, but has been regularly deployed as a centre-back during his time with the Spanish club.
The World Cup finalist returned to his usual position on Saturday, however, as Barca continued their unbeaten start to the season.
"There are things to improve but we are on the right line," he told AS.
"We leave with the feelings of a victory and it's against an opponent that's not easy to beat. I was happy to play for Barca in midfield."
Barca are still yet to concede in the league this season and sit top of the table after eight games.