Bayern dominated possession in the first period, but trailed to a Karim Benzema strike at the interval.
The away side also had more of the ball in the second 45 minutes, but could not make the breakthrough as Madrid secured a one-goal advantage ahead of the second leg next week.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
MADRID: Casillas; Carvajal, Pepe, Ramos, Coentrao; Modric, Alonso, Isco; Di Maria, Benzema, Ronaldo
BAYERN: Neuer; Rafinha, Boateng, Dante, Alaba; Kroos, Lahm, Schweinsteiger; Robben, Mandzukic, Ribery
Bernabeu in shade as sun goes down pic.twitter.com/waw53YvDhS— Oliver Holt (@OllieHolt22) April 23, 2014
All seven of Bayern Munich's goals in this season's knockout stages of the Champions League have been scored from the 54th minute onwards.— Betfair Exchange (@BetfairSports) April 23, 2014
I suspect tonight's Champions League semi will be a proper game of football. 2 teams with one thing in mind; to attack!— Gary Lineker (@GaryLineker) April 23, 2014
Leaping chest bump. pic.twitter.com/bALuTpgPFB— AS English (@English_AS) April 23, 2014
> Ancelotti leading 1-0 at HT (at home): 248 wins, 21 draws, 2 losses > Guardiola trailing 1-0 at HT (away): 9 wins, 7 draws, 6 losses— MisterChip (English) (@MisterChiping) April 23, 2014