If Bayern Munich are to have any chance of a sixth straight semifinal appearance in the Champions League it will have to do something that only one team has achieved this season — defeat Real Madrid at the Santiago Bernabeu Stadium.
Winning in Madrid is no easy task and even a 1-0 victory on Tuesday will not be enough after a 2-1 first-leg, quarterfinal loss in Munich.
Celta Vigo's 2-1 win in the Copa del Rey in January gave Madrid it's only loss in 23 games at the Santiago Bernabeu this season, where Zinedine Zidane's team has won 15 times and drawn five.
In the Champions League, the defending European champions haven't lost at home in 12 consecutive matches, winning nine of the last 10.
Bayern has only managed two wins in 12 matches against Madrid at the Bernabeu.
"We'll go there and try to turn the tide," Bayern defender Philipp Lahm said. "It won't be easy, we're the underdogs. But we'll have a chance to win in Madrid."
Madrid had most of its regular starters available for the loss to Celta in the Copa del Rey quarterfinals, when it couldn't come back after conceding two goals on counterattacks in the second half. Madrid was eventually eliminated 4-3 on aggregate after a 2-2 draw in Vigo.
Madrid is trying to become the first team to defend the title since the competition's new format was created in 1992-93. Madrid defeated city rival Atletico Madrid in the final both in 2014 and 2016.
"It'll be a great game," said Bayern coach Carlo Ancelotti, who led Madrid to the 2014 title. "We believe in ourselves and we'll give it everything."
Only two teams have reversed a first-leg home loss in Champions League history — when Inter Milan eliminated Bayern in 2010-11 and Ajax got past Panathinaikos in 1995-96.
Bayern had been the dominant home team in the Champions League until last week's loss ended its run of 16 consecutive home wins in the competition.
Cristiano Ronaldo scored both goals for Madrid in the come-from-behind win in the first leg, becoming the first player to reach 100 goals in European competition. He is three short of the 100th-goal mark in the Champions League.
The Portuguese forward was among the Madrid players rested by Zidane in Saturday's 3-2 win at Sporting Gijon in the Spanish league, a result that kept Los Blancos ahead of Barcelona in the standings.
Madrid forward Gareth Bale remains doubtful for Tuesday's game with a right leg injury, along with defenders Pepe and Raphael Varane.
Robert Lewandowski, who is recovering from a right shoulder injury that ruled him out of the first leg, should be available for Bayern. The Poland striker has scored 38 goals across all competitions this season.
"I'm doing well," Lewandowski said on Sunday.
Bayern teammates Mats Hummels and Jerome Boateng also have been nursing injuries, while Javi Martinez is suspended.