Returned to the Santiago Bernabéu Stadium, Serena went on appear in 86 competitive matches (15 goals) and be part of the squads that won four national championships and the 1965–66 edition of the European Cup. In the latter competition, he scored the winning goal in the final against FK Partizan, controlling the ball with his chest and volleying in from outside the box in a 2–1 win in Brussels.