The in-form Barca failed to break down a stubborn Espanyol in Wednesday's first leg as the semi-final spot remains up for grabs.

"It is not a bad result, but is also not great," Guardiola was quoted as saying by Barcelona's official website.

"In the cup it is good to score away from home and have done that. We are now obliged to be attentive in the second leg."

Guardiola rested most of his key players, including Samuel Eto'o, Thierry Henry, Daniel Alves, Eric Abidal, Victor Valdes and Yaya Toure.

Xavi and Lionel Messi came on as second-half substitutes but couldn't help Barcelona find the net.

"There were a lot of interruptions that did not help us and meant that we could not find our rhythm of play," Guardiola added.

"We have not managed to find a way through or to connect in midfield."