BUCHAREST (Reuters) - Steaua Bucharest completed a domestic treble when they outclassed Universitatea Cluj 3-0 in the Romanian Cup final at the National Arena on Sunday. Adrian Popa put on a brilliant display, scoring a goal in each half for Steaua who won the Cup for the 22nd time, with Raul Rusescu also netting three minutes after the break. It was a dream farewell for Steaua coach Constantin Galca, who will be replaced by former Romania international Mirel Radoi at the end of the season. Steaua also won the Romanian league title and the League Cup earlier this month. (Reporting by Angel Krasimirov; Editing by Ken Ferris)