Barcelona coach Gerardo Martino has said that there is more to come from his side following their 4-0 Champions League victory over Ajax.

Lionel Messi grabbed a hat-trick at Camp Nou on Wednesday, with Gerard Pique also getting on the scoresheet.

"We were better in the second half and in the passing game," Martino told reporters. "We did not play well in the first half, with many long balls.

"We still made mistakes, but we are improving game by game. It is very important for me and for the club to begin with a victory in the Champions League group stage."

Barcelona's next European game sees them take on Celtic on October 1.