Bayern Munich coach Pep Guardiola said a slow start cost his side in Wednesday night's Champions League semifinal first leg at the Estadio Vicente Calderon.
Atletico midfielder Saul Niguez's solo strike on just 11 minutes was the game's only goal, making it the third straight season Guardiola's Bayern have lost a semi away against La Liga opposition.
Bayern dominated possession for long spells, but Atletico could dig in with the lead to protect, and the visitors closest to a breakthrough was a 35-yard piledriver from centre-back David Alaba which crashed back off the crossbar.
The Catalan coach told his postgame news conference that overall he was happy with how his team had played, while ruing that it had taken them too long to get going.
"I am happy with the performance of the team," Guardiola said. "It was a good game overall, but we started badly. The goal was a consequence of our slow play. The last 25 minutes of the first half, and during the whole second half, we did well. I am not so content with the result. They scored early, which marked the game, a fantastic goal from Saul. We still have 90 minutes to play, and we will keep going until the end."
Before tonight Bayern had failed to score in only two of their past 30 matches in all competitions. But today they were up against an Atletico side which has conceded in just three of their 17 home Champions League matches during Simeone's time in charge.
Guardiola said he thought his side had created enough chances to have scored at least once, while recalling how difficult all teams found it against Atletico.
"We need to think about who we were playing, the team that Atletico Madrid are," Guardiola said. "They have a very good goalkeeper, they defended very well, with many people inside, it is not easy. Teams make very few chances against Atletico, we did create some, that is an argument we can make, not an excuse. We did not start well, but we played enough to score."
The ex-Barcelona boss was asked by a Spanish reporter if Saul's spectacular solo goal reminded him of his one-time Blaugrana star Lionel Messi.
"I admire Saul's quality a lot, but you cannot really compare him with Messi," was the measured response. "I have seen him before, he is a great player, Spanish football has another great talent.
Guardiola explained his surprise selection decision to leave regular starter Thomas Muller on the bench to start 20-year-old French winger Kingsley Coman.
"We wanted to have aggression and depth in our play, to make the pitch wide, on both sides," he said. "[Atletico full-backs] Felipe Luis and Juanfran had their problems in defence."
Although this was the same first-leg result as the 1-0 defeat at Real Madrid two years ago, Guardiola said he hoped his side would deal better with the situation than when Cristiano Ronaldo & Co. won 4-0 in Munich in that season's return game.
"I don't know if we have learned our lesson or not," he said. "This is a new situation. In Bernabeu we made more chances than here. Madrid closed up very well -- and were able to counterattack really well, we hope this time to deal better with Atletico's counter.
"We know who we are playing against. We did enough to score a goal. We will see on Saturday if we can win the Bundesliga, then we will see about Tuesday. I want to watch the game again, calmly."