Gago completed his switch yesterday.
"I have come with a clear goal," he told reporters. "I like to win titles and in all my career I have won titles, so I do not want this season to be like my last one, in which I did not win anything.
"It was a quick decision and I made it thinking about the city, which is amazing, and also about my family and sporting matters.
"A friend of mine told me great things about this club and I think it was the best decision. I really liked this club's project because they have very good players."