Catalans must avoid complacency.
Gerard Pique said Barcelona must avoid making the mistake that cost Paris Saint-Germain a Champions League quarter-final spot.
The Barca defender says their battle against Manchester United is not yet over despite winning 1-0 in the first leg of their quarter final clash at Old Trafford on Wednesday night.
It was Barca's first European triumph away to United, and Pique says they must avoid complacency after what happened to PSG in the last 16.
"After seeing what they did against PSG there's no reason at all to believe the tie is over," Pique told reporters as Marca reported.
"PSG were the clear favourites then, they played far better and look what happened. Anything can happen in football, so we'll have to focus very hard."
He added: "We put in an excellent performance defensively, we're in our best form in defence of the season.
"The early goal relaxed us and we knew how to cope with the situation, the fact we didn’t concede helps us a lot.
"It's very difficult to come here, it's an historical ground, there's a sensational atmosphere and you get put under a lot of pressure."