Willock aims to make his bid next season under coach Rui Vitoria.
He said: "I hope I can play regularly in the first team, I want the coach to know that I will be ready next season.
"I know that if I play well and work hard, I will have opportunities and I want to take advantage of them."
Willock left the Gunners last summer and is happy with his first season in Portugal.
He added: "I like the technical aspects of the game and this is one of my virtues, which was a great reason to go there. I always wanted to play abroad at some point in my career but I never thought it could happen so soon. Benfica contacted me in the summer, I went to visit them and they convinced me that it was there that I wanted to play in the next few years."