A Heung Min Son goal midway through the second half was enough to earn Sami Hyypiä's men all three points and move them to within ten points of Bayern, and perhaps more importantly, increase the gap over third-placed Borussia Dortmund to seven points.
Long wait for chances
Both sides sized each other up, not wanting to give an inch in a tense opening. An injury to Lars Bender, who was able to continue, disrupted the opening, but neither side seemed to be developing a rhythm anyway. The hosts got their foot on the ball more often, but lacked invention, even though Granit Xhaka was looking intently for openings.
The first arrived for Patrick Herrmann, whose volley from outside the area was saved well by Bernd Leno. Max Kruse saw his shot on the turn flick off the head of Roberto Hilbert behind for a corner, but still there was no sign of an opening goal, especially not at the other end of the field. Indeed, it was not until the 39th minute that Kießling tried to make room for a shot, but Leverkusen's first effort on goal, coming shortly before the interval, was easy pickings for Marc-Andre ter Stegen.
Upsetting the odds
Son tried from an even more unlikely position 25 yards out, sending his shot over the crossbar before apologising to his team-mates for a rare chance which went begging. Ominously, each time Leverkusen had failed to score in the first half this season, they left the field beaten (by Schalke, Braunschweig, Frankfurt and Bremen).
Their first half performance had shown little reason why that statistic would change this time, but something special arrived to alter that. Sam, inconspicuous for much of the game, squared the ball to Son, who settled himself and curled an effort beyond the lunge of Martin Stranzl and past a statuesque ter Stegen. Out of nothing, Leverkusen had the lead.
Another statistic suddenly suggested Leverkusen were not going to lose: the last 12 games Son had scored in, Leverkusen had won, including a 1-0 win over Borussia Dortmund. It was Leverkusen's turn to try to prove the statistics wrong, and they set about the task diligently. Branimir Hrgota was sent on by Lucien Favre, who tried to mix things up in his attack.
Juan Arango came the closest, but Leno punched his effort from distance out to safety with ten minutes remaining. It was not to be once again for Gladbach, who fell to their second straight home defeat after going the entire first half of the season without losing at home. Furthermore, it is the first time ever that the Foals have lost the first three games of the second half of a season.
Line-ups and statistics