Dortmund to lose top spot after 'Gladbach defeat
Moenchengladbach's goalkeeper Marc-Andre ter Stegen (C) and Dortmund's striker Robert Lewandowski (L) jump for the ball during their German first division Bundesliga football match in the western German city of Moenchengladbach on October 5, 2013
Either Pep Guardiola's second-placed Bayern Munich or Sami Hyypia's third-placed Bayer Leverkusen can claim top spot when they meet later Saturday.
Fresh from their impressive 3-0 Champions League win over Marseille, Dortmund were set to claim an away point until a disastrous final 10-minute spell.
Hummels earned a red-card on 81 minutes with a reckless challenge on 'Gladbach's Norway midfielder Havard Nordtveit in the area which left referee Manuel Graefe reaching for the red card.
Germany striker Max Kruse netted the resulting penalty, then Brazilian forward Raffael hit their second four minutes from time to see 'Gladbach move up to fourth.
"That was an unusual game, we had our opponents under brutal pressure for long periods of play, but didn't score," admitted Dortmund coach Jurgen Klopp.
"We played our part in the defeat, we left the game too open and allowed 'Gladbach to come to life when they took their chances."
Dortmund midfielder Sven Bender is an injury doubt for Germany's World Cup qualifiers against Republic of Ireland on Friday and Sweden four days later after being left bruised by a second-half challenge.
Schalke 04 came from behind to claim a 4-1 win over 10-man Augsburg in Gelsenkirchen to move up to eighth.
The visitors took a shock lead when Augbsurg striker Sascha Moelders netted when his half-volley from a cross looped over Schalke goalkeeper Timo Hildebrand with 10 minutes gone.
Just six minutes later, Augsburg defender Ragnar Klavan was shown a straight red card for bringing down Schalke's Hungary striker Adam Szalai with Ghana midfielder Kevin-Prince Boateng slotting home the resulting penalty.
Szalai then put his side ahead when he converted a pass from Japan right-back Atsuto Uchida with 28 minutes gone before netting his second 12 minutes from time when he tapped home a pass from Germany left-back Dennis Aogo while 18-year-old midfielder Max Meyer netted a late fourth.
VfB Stuttgart dropped to seventh after their 1-1 draw at home to Werder Bremen while Hoffenheim, who narrowly avoided relegation last season, stayed 10th with a 2-2 draw at Mainz.
Eintracht Braunschweig, who had spent the season thus far bottom of the table since last season's promotion, picked up their first win of the season with a shock 2-0 victory at VfL Wolfsburg -- their first Bundesliga victory since 1985.
Midfielder Karim Bellarabi scored the opening goal after 30 minutes before Congo forward Domi Kumbela put the result beyond doubt with a late second.
The win lifted Braunschweig off bottom place with Freiburg, who host Frankfurt on Sunday, dropping down to last place.
On Sunday, Bert van Marwijk, the former Holland manager, is seeking his first win as Hamburg coach at Nuremberg.