Chelsea take on the Czech side at Stamford Bridge on Thursday night in their last-32 clash after securing a 1-0 victory away from home in the first leg last week.
And despite Benitez's men trailing weekend opponents Manchester City by four points in the Premier League, the Blues boss says domestic matters take a backseat until Thursday's game is out the way.
Benitez said: "Usually the manager has to keep an eye on everything if he can but the priority will obviously be this game.
"At the moment the Europa League is the priority because we will play against them tomorrow. One game at a time, and this is the most important game we have to play.
"I think it's an important competition for us and after we'll have a massive game at Manchester City. Obviously if we beat them we will be closer, if not we have to carry on."