"A victory like this gives us the confidence to continue growing," said De Jong after Leganes win.
"In addition to the five goals we scored, we've managed to refine the positioning of our players," De Jong said in his post-match interview.
"We have improved with regards to the match against Valencia.
"I don't think we have an issue with the system.
"It's more a case of the players' position during a match.
"It's been good to regain confidence after losing to Valencia, but now we have to think about next weekend."