Borussia Dortmund's title hopes took another blow at the Allianz Stadium when Erling Haaland was forced off in discomfort during the second half of Der Klassiker against Bayern Munich.
The Norwegian sensation and BVB went into Tuesday's clash needing a win to close the gap on Bayern at the top of the table, after both teams recorded back-to-back wins in their first two fixtures following the return of the German top flight in May.
But Dortmund's hopes were dealt a blow in the first 45 minutes when Joshua Kimmich's shot looped over Roman Burki and into the net to open the scoring.
Midway through the second half, their chances of taking something from the clash were made to look even more remote when Haaland limped off the pitch.
The forward pulled up with 70 minutes on the clock in some pain, although he initially attempted to continue with his side looking to come back from 1-0 down.
After chasing a Jadon Sancho cross out of play, however, Haaland went to the floor and it immediately became apparent he would play no further part in the encounter.
Dortmund coach Lucien Favre sent Giovanni Reyna, who was already warming up in anticipation of an imminent substitution, onto the field, while Haaland limped off behind the Bayern goal and made his way slowly to the away bench.
Now the Rhinelanders will face a nervous wait to find out whether the injury, which at first glance appeared to be a muscular complaint in the player's right leg, proves serious enough as to keep him out for a significant part of the title run-in.
With 10 goals in just 12 league appearances since making the switch from Red Bull Salzburg in January, the youngster's potency in front of the net has been key in keeping BVB's challenge for the crown alive.
Currently second in the Bundesliga standings, Dortmund are back in action on Sunday away to Paderborn, before hosting Hertha Berlin the following Saturday.
A Bayern victory on Tuesday will mean the Bavarians open a seven-point advantage at the Bundesliga summit with just six games left to play, leaving them on the verge of a record eighth consecutive title.