Bayern Munich coach Jupp Heynckes says his side "will have to play better" if they want to win the Champions League this season.
Bayern earned a hard-fought 2-1 victory over an impressive Sevilla side in their quarterfinal first-leg tie at the Ramon Sanchez Pizjuan on Tuesday.
Pablo Sarabia opened the scoring for La Liga's seventh-placed side on 32 minutes, taking advantage of poor defending by Bayern's Juan Bernat, who was deputising for first-choice left-back David Alaba.
James Rodriguez replaced an injured Arturo Vidal four minutes later and made an explosive impact. James played in Franck Ribery with his first touch of the ball and Bayern's longest-serving player saw his cross agonisingly turned into the Sevilla net by former Manchester City winger Jesus Navas.
Sevilla matched the nervy German champions for long periods. However, things got even better for Bayern on 68 minutes when Thiago's back-post header took a wicked deflection off Sergio Escudero for the winning goal.
Speaking after his 12th straight win in the competition, Heynckes told Sky: "It was vitally important to equalise right away.
"It was definitely a little bit fortunate but that's football. It's always psychologically an advantage to score or take the lead shortly before half-time."
Brazil defender Rafinha came on for the ineffective Bernat after the interval.
"If we want to win the Champions League, then we will have to play better," Heynckes warned, before paying tribute to his substitutes' impacts.
"Both of our substitutes [James Rodriguez and Rafinha] reinvigorated us. Our play had more fluidity, we gained more possession and were able to score a couple of goals. Until the final few minutes when Sevilla threw everything at us, we were well in control of the game.
"Both changes were forced by injury. Arturo Vidal picked up a knee injury, while Juan Bernat sustained a flesh wound on his ankle."
However, Heynckes admitted his side were second-best in the opening period.
"Sevilla definitely had the better of the first half, we gave the ball away too often. We were all over the place in midfield, which enabled Sevilla to create a lot of chances," Heynckes said.
"We made a few changes and won deservedly in the end on account of our second-half performance."
Defender Mats Hummels agreed there was room for improvement.
He told BT Sport: "I think the result would have gotten our signature if you gave it to us before the game, so we're very happy about the result and about most parts of the game as well, but it wasn't 90 minutes of good from us.
"[There was] at least half-an-hour in the first half when Sevilla were clearly the better team and had good chances to score maybe a second goal, so we know there's a lot we have to improve in the next game next week, and hopefully in the games coming after that.''
Hummels insisted Sevilla's performance did not catch them unawares, saying: "We always told everyone how good they are because we knew.
"So it didn't come as a surprise for us, but of course we didn't want them to be that dominant for the biggest part of the first half.
"That's something we will analyse and talk about and we will try not to let it happen again in next week's game in Munich.''
Sevilla coach Vincenzo Montella, whose side dumped Manchester United out in the previous round following a 2-1 win at Old Trafford, admits the Andalusian outfit have a mountain to climb but is not throwing in the towel yet.
Asked what chance they have in the return leg, Montella said: "Few, but we're going to play with the same amount of pride, or more.
"Things are made possible if you believe and I continue believing.
"Our percentage [of going through] is low, but we have to play them.''
He added in his postmatch newsconference in quotes reported by AS: "We haven't had luck. I'm grateful for the excellent game that my players had against a very high-level opponent.
"The team deserved more. The first goal we conceded was a shame, it didn't demoralise us, but we lost momentum.
"The second half was more even, but we didn't have the energy to go on the counter-attack.
"We went for it in the final minutes and I like that a lot, but the two goals [Sevilla conceded] were a shame.''
Press Association contributed to this report.