The striker left West Ham last month to sign for Alaves and admits he never felt "trusted" when in the Premier League.
He explained, "The main thing for a player is that they trust you, and that has not happened in the Premier League.
"It is true that I played the Champions League with Arsenal but they did not trust you and so you lose confidence as a player.
"Mainly I am for that reason with Alavés now, because they have bet on me."
Lucas added: "For me it is a challenge to score goals and help the team.
"The goal is permanency, but I do not want to focus on that but to make a better season than what has been done last season."