The two teams will meet again at the Camp Nou on August 8 with the scores tied at 1-1 after the first leg in Italy.
Antoine Griezmann’s away goal means Barca have the slight edge, and Mertens knows his team will have to go on the attack.
“It’s not going to be easy but we’re feeling confident. The key is that we have to score because if we don’t score, we will be out. If you prepare for it, then maybe you never know what can happen.”
Source | Football Italia
Barcelona will have to cope without Arturo Vidal and Sergio Busquets for the match, as both midfielders are out through to suspension.
The winners of the tie are likely to face Bayern Munich in the quarter-finals in Lisbon.