A schoolboy howler by goalkeeper Oliver Kahn cost Bayern Munich an almost certain victory as they drew 1-1 with Real Madrid in the glamour tie of the Champions League's first knockout phase.
Holders AC Milan also had to settle for a draw in a goalless first leg at Sparta Prague, but Lokomotiv Moscow held on for a 2-1 home win over Monaco.
The night will be one to forget for Germany captain Kahn after he allowed a long-range free kick by Real's Brazil wingback Roberto Carlos to slip under his body when he seemed to have the ball well under control.
Voted FIFA's player of the tournament at the 2002 World Cup, Kahn made his blunder with just seven minutes to go at the Olympic Stadium after Dutch striker Roy Makaay had headed the hosts into a well-deserved lead in the 75th minute.
The away goal means Real will now fancy their chances of reaching the quarter-finals when they face the Germans at the Bernabeu in a fortnight's time.
Milan will rue a couple of missed chances by their Ukrainian striker Andriy Shevchenko in Prague and can now ill-afford any defensive slips at the San Siro.
The away goals rule will keep Monaco's hopes up after their consolation strike by Fernando Morientes in a snow-swept game in Moscow, but will give little encouragement to Celta Vigo.
