Barcelona coach Pep Guardiola said he was happy with his young team's performance despite losing 1-0 to Manchester City, and appealed for patience from fans over new star signing Zlatan Ibrahimovic.

Bulgarian winger Martin Petrov scored in the 28th minute against the run of play to beat the Spanish and European champions and take the annual pre-season Joan Gamper Trophy for the big-spending English Premiership side on Wednesday.

Guardiola brought in a lot of young reserve team players and left many of his big stars on the bench.

"I am very happy with their performance, young players facing a quality team like Manchester City. We are fortunate to have a good pool," he said.

"I made many changes, and the youngsters responded very well."

The most anticipated moment came in the second half, when Ibrahimovic and Argentine Lionel Messi, two of the top-rated strikers in the world, came on.

The Swede almost scored in the 74th minute, but his shot lacked force.

It was his first match for the club since his transfer from Inter Milan this summer and since undergoing surgery on a broken hand last month.

Guardiola appealed to fans to give him some time to adapt.

"He has come for four or five years, not for one day," he said, adding that combining with his teammates "takes a bit of learning."

The player himself said he is just trying to find his "rythmn" in the new team.

"I played 45 minutes and I tried not to think about the injury to my hand. It bothered me a bit, but I play with my feet not with my hands."

The Catalan giants, who won a unique treble of Spanish league, Cup and European Champions League last season, face Athletic Bilbao on Sunday in the return leg of the Spanish Supercup.

On August 28, they play Ukraine's Shakhtar Donetsk in the European Supercup.

The Spanish league season begins on the weekend of August 29-30.