Barca ran out winners in the game to extend their lead at the top of La Liga to seven points, but the Barca boss felt the result was harsh on the hosts.
"The result was misleading and excessive because Leganes made it difficult for us and had a great game, while there were times when we weren't brilliant," Valverde admitted following the game.
"They're very secure at the back, as shown by the fact that they've only conceded two goals in five games."
Luis Suarez starred for Barca, scorring twice as he finally ended his barren spell in front of goal, with Valverde insisting that he was never concerned by the Uruguayan's form.
"Suarez? We need his goals, as well as those of Lionel Messi, Paco Alcacer and others, such as Paulinho," he said.
"We already know our forwards always relate well with our opponents' goal and that sooner or later, the goals will come.
"Now people will calm down about Suarez. We'll see what happens next."