The Dutchman was in bullish mood after the reigning European champions were drawn against the struggling Red Devils - but says David Moyes' men remain a "very good team"
The runaway Bundesliga leaders visit Old Trafford in the first leg on April 1 before the return at the Allianz Arena a week later.
Robben, who scored the winner in last season’s final victory over Borussia Dortmund at Wembley, was in a confident mood after learning of Bayern's next assignment.
“It is a great draw,” he told Sky Sports News. “I look forward to these matches.
“We play away from home in the first leg. That is an advantage.
“Manchester is not in the best shape. But it still is a very good team.”
Bayern skipper Philipp Lahm was more circumspect and insisted they will not be fooled by United’s domestic struggles when they face David Moyes’ side.
United are languishing in seventh place in the Premier League in what has been a difficult season but Lahm is still expecting a tough tie.
The Germany full-back said: “We should not be blinded by the standings in England. We have to perform well in both matches. Then we'll have a good chance to progress to the semi-finals.
“We are the holders and we are the favorites in these kind of matches.”