BERLIN (AP) — Borussia Dortmund is facing a crisis after the club's worst start in 48 years of competing in the Bundesliga left the 2011 and 2012 champion joint-bottom on Sunday.

Saturday's 2-1 defeat at great rival Bayern Munich was the club's seventh in 10 games, its fifth in a row, heightening the sense of alarm as on-field efforts fail to yield any reward domestically.

"Every defeat hurts and the pain increases with the frequency with which we're losing in the Bundesliga," said Dortmund coach Juergen Klopp, whose side has already lost as many league games as in the whole of last season.

"It's anything but good, what has happened," Klopp said. "We've a lot of construction sites and many of the defeats are self-inflicted."

Two mistakes from Neven Subotic cost Klopp's side dearly in Munich — a clearance went straight to former teammate Robert Lewandowski for the equalizer and the defender conceded a penalty after Franck Ribery blocked another attempted clearance — but the 2-1 scoreline arguably flattered Dortmund, which had only four efforts on target compared to Bayern's 18.

Roman Weidenfeller produced an inspired performance by making 12 saves, a Bundesliga record this season and a personal league best, but they weren't enough in the face of Bayern's incessant pressure.

Dortmund has conceded in every league game this season, and only Werder Bremen, Stuttgart and Eintracht Frankfurt have conceded more. Only goal difference separated Dortmund from bottom side Bremen.

Klopp's position is not under threat, not yet at least, due to the success he brought Dortmund since taking over in 2008. Back-to-back Bundesliga titles were complemented by the club's first league and cup double in 2012, and the former Mainz player then led Dortmund to the Champions League final in 2013, only for Bayern to emerge victorious thanks to Arjen Robben's late winner.

Robben converted the penalty on Saturday, underlining the Dutchman's stature as Dortmund's tormentor-in-chief.

Klopp's side hasn't been helped by injuries — Henrikh Mkhitaryan, Marco Reus, Jakub Blaszczykowski, Ilkay Gundogan, Marcel Schmelzer, Nuri Sahin and Oliver Kirch have all faced long spells out — and captain Mats Hummels was ruled out for three weeks with a right foot sprain on Sunday, sustained against Bayern the night before.

Goals are also proving scarce following Lewandowski's switch to Bayern.

After 10 league games last season, Dortmund was second in the table with 25 goals scored, three more than leader Bayern. The side has only 11 goals at the same stage this season.

Klopp has been rotating three strikers — Ciro Immobile, Pierre-Emerick Aubameyang and Adrian Ramos — to try and fill the void but none are as yet proving as effective as Lewandowski.

The Polish striker joined Bayern in the offseason, following Bayern's capture of Mario Goetze the year before, and Dortmund is facing the possibility of Marco Reus joining his former teammates in Munich next season.

Bayern chairman Karl-Heinz Rummenigge angered Dortmund management by saying Reus, who has a contract to 2017, could leave for 25 million euros ($31.3 million) next summer.

"We'll discuss it internally in peace and calm and then make a decision," Rummenigge added weeks later. "The player also has to decide."

Reus covered his ears after scoring against Bayern, suggesting he didn't want to hear any more media speculation on his future, but it's likely to continue until he makes a statement one way or the other.

Dortmund CEO Hans-Joachim Watzke has hit out at Rummenigge for continuing to fan the flames and said Saturday that he no longer had any working relationship with the Bayern chairman.

Bayern, meanwhile, is taking pleasure from Dortmund's travails. Fans celebrated their side's deserved win by chanting Dortmund will be playing in the second division.

"It's a lovely feeling to beat Dortmund, even if they're not where they should be in the table," said Thomas Mueller, whose side appears to have the Bundesliga wrapped up already after 10 games.

Bayern sporting director Matthias Sammer said his side wasn't to blame if the Bundesliga was becoming less interesting.

"It's up to the league to provide the excitement, not us," said Sammer, a former Bundesliga-winning Dortmund player and coach, who did little to quell talk of Reus joining the club. "Marco Reus is a Borussia Dortmund player. We discuss what thoughts we have internally."

Of more pressing importance to Dortmund now is the side's league position.

"It's lousy of course," Klopp said. "But you can get confidence back, so that's the cool thing."