Berlin - Pep Guardiola and Xabi Alonso think Bayern Munich will have their work cut out when they face 'monsters of passion' Atletico Madrid away in their Champions League semi-final, first leg.
Madrid host the first leg at their cauldron-like Vicente Calderon stadium on April 27 before the return leg at Munich's Allianz Arena on May 3.
"The atmosphere there is the best in Europe," Bayern's Guardiola said of the Atletico ground in a press conference in Munich.
"I am very curious about this game, it will be big experience for all the players and the fans there will support their team for the full 90 minutes," added Guardiola.
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He has a perfect record of seven Champions League semi-final appearances in seven years with both Barcelona (from 2008-2012) and Bayern (2013-16).
But Guardiola was full of praise for Atletico's Argentinian coach Diego Simeone, who steered his team to the 2014 Champions League final and knocked Barcelona out in the quarter-finals.
While Atletico's forwards Fernando Torres and Antoine Griezmann tend to grab the headlines, Guadiola said Madrid's Uruguay defender Diego Godin and Slovenian goalkeeper Jan Oblak are the reasons they concede few goals.
Guardiola praised Simeone, who took charge in 2011, for turning Atletico from Spanish league also-rans to the team which humbled Champions League holders Barcelona.
"I never trained with him or played against him (during my career), I don't know him and I've spoken to him perhaps twice," said Guardiola.
"But his players do exactly what he wants and they follow him without any doubts.
"He's perhaps one of the best coaches in the world.
"Over ten years Atletico didn't beat Real Madrid, then Simeone arrived and changed all that."
Bayern's veteran Spain international midfielder Alonso said the Germans can expect a tough test in Madrid and only a good performance will silence the local support.
"Like Pep, Simeone has a lot of passion. He's a good coach, but we'll have to blend all of that out and focus on ourselves," said Alonso.
"If we play well, then the atmosphere won't be a deciding factor.
"They don't concede many goals and there is always an unbelievable atmosphere for home matches.
"We want to make sure we get a good result from the first leg."
Sammer says Bayern will face two 'monsters of passion' in Atletico and Simeone.
"It will be extreme against Atletico and we have a lot of respect, but we also have a few players who can stop them and limit the tempo," said Bayern director of sport Matthias Sammer.
"Atletico are monsters of passion, they are honest and authentic, from what I have seen."
Bayern host Schalke on Saturday in the Bundesliga holding a seven point lead over second-placed Borussia Dortmund.
Sammer says Bayern can not afford to give any more points away in their bid to become the first club to win four straight Bundesliga titles.
He is convinced Dortmund's dramatic 4-3 defeat to Liverpool in the Europa League quarter-final, second leg, will only serve to boost their domestic performances.
"I say with full conviction; Dortmund will not give any more points away," he said.
"Their mourning from yesterday will be converted into energy, so Saturday's game against Schalke is like a final for us."