Bayer Leverkusen ended Inter Milan’s unbeaten Champions League record after claiming a dramatic 1-0 victory at the BayArena.
Nordi Mukiele struck in the 90th minute to inflict a first defeat across six games in this season’s competition on Inter.
Simone Inzaghi’s team looked to be hanging on for a point from a game Bayer dominated in terms of attacking opportunities.
The German club had more than 60 per cent possession and 17 shots, compared to Inter’s six, but Mukiele came up trumps to seal maximum points.
It was also the first goal Inter had conceded in this season’s tournament but they remain firmly on course for the next phase, along with their conquerors.
Bayer were quickest out of the blocks and went close to taking a fourth-minute lead when Jeremie Frimpong’s cross found Nathan Tella, whose shot hit the crossbar with Inter goalkeeper Yann Sommer beaten.
Inter were initially sluggish in comparison and a first half-chance came 10 minutes later when Hakan Calhanoglu’s effort was deflected into the arms of Bayer goalkeeper Matej Kovar.
Calhanoglu was then booked for dissent and Bayer pressed again but Exequiel Palacios saw his long-range shot fly narrowly over the bar.
Carlos Augusto became the second Inter player to collect a yellow card, yet the visitors were showing more promising attacking signs until being forced on to the back foot again as Florian Wirtz shot narrowly wide.
Inter’s Alessandro Bastoni was off-target with a header on the stroke of half-time, yet the Italians went in at the break on level terms despite playing second fiddle for lengthy spells.
Bayer began the second half brightly, with Tella having a shot blocked before Mukiele failed to find the target after being freed by Granit Xhaka.
Inter could offer little in reply and Frimpong was next to threaten, sending a shot narrowly wide before Inzaghi made a triple 66th-minute substitution, sending on Lautaro Martinez, Nicolo Barella and Kristjan Asllani.
Inter had barely got into the game after half-time and Bayer continued to monopolise territory and possession in pursuit of a fourth Champions League win on the back of three successive Bundesliga victories.
Chance after chance went astray but just when it looked as Bayer would draw a blank, Mukiele found the target to clinch a richly-deserved success for his team.