The sides will face each other in the competition's last eight following Friday's draw in Nyon, evoking memories of the dramatic 1999 final when United scored two stoppage-time goals to claim a last-gasp victory at Camp Nou.
United's first season under David Moyes has not gone according to plan - his team currently sit seventh in the Premier League - but Lahm feels the tie will still be as big a challenge as ever for the defending champions.
"We can't allow Manchester United's current position in the Premier League table to affect our mindset for this game," he is quoted as saying by UEFA.com.
"We will travel to Manchester in order to play attacking football and score goals."
And Bayern sporting director Matthias Sammer echoed those comments, adding: "On good days, they are really dangerous. We've got to make sure they don't have two good days."
United required a 3-0 second-leg win to get past Olympiacos of Greece 3-2 on aggregate in the last round, while Bayern triumphed 3-1 over two legs against Arsenal.
The first leg will take place on April 1-2, with the return games one week later.
