The FA Cup remains United's only realistic target of silverware this season as they prepare to host rivals Arsenal for a place in the competition's final four.
However, with United in the midst of a five-way battle to finish in the Premier League's top four, Van Gaal insists leading the Manchester club back into the Champions League is his main target.
"I want to get always the goals that we have set, and the goals we have set is the top four, and a trophy would be fantastic," Van Gaal said.
"It's fantastic for the players and the manager but our role in our first year together is to win a place in the Champions League.
"I think that Arsene Wenger is right - I think that Arsene Wenger is always saying right things - for a club, Champions League is the highest level and that's why he's saying that.
"To finish in the first four is a fantastic result and for us at Manchester United even more I think. If you win the FA Cup you are not in the Champions League but you have won a title."
