There's no reason for Madrid to underestimate Bayern
They have always been one of the most dominant team in the UCL in recent years so caution would be employed while playing them no matter their form.
Madrid can be considered a favored child in UCL
No matter their form
They always are the likeliest to win the trophy and who ever manages to win them has already won the UCL. [/quote]
Underestimating Bayern Munich is a big mistake, of course. Bayern Munich has a squad that is capable of destroying Real Madrid's defense, and Real Madrid could even lose badly from the first leg if Ancelotti underestimated them. But what is certain is that Ancelotti will not do that and as a form of his seriousness in winning the title, Ancelotti will use every best player to win the match.

Harry Kane is the best center forward so far that Bayern Munich has. He is a reliable player who can find the back of the net for Real Madrid when he has the chance, so if Real Madrid don't defend as well as they did when they held Manchester City to a draw, then I think Real Madrid will lose.