Athletic travelled to the Turkish capital looking to maintain their unbeaten record in the UEL against a Fenerbahçe side they were taking on for the first time in a competitive match.
The gap in points showed in the early exchanges, as the hosts were quick to press the Basque side into their half as boos whistled around the Şükrü Saracoğlu Stadium.
Despite that early pressure, it was the home side who cracked first when Samet Akaydin attempted to play a slow and sloppy pass back to his keeper which was stolen by the advancing Gorka Guruzeta, who calmly passed the ball to his right to give Iñaki Williams a simple tap in for the lead.
Fenerbahçe didn’t let the early goal deter them as they went straight back to pressing their opponents, with the two sides tussling in the midfield for the majority of the half.
Although the visitors did get the chance to extend their lead when Guruzeta was played into the box, the striker's shot was expertly pushed away by Dominik Livaković.
With HT approaching, Mert Müldür nearly levelled the game with a curling effort from the edge of the box, but the full-back's strike flew inches wide of the far post.
That missed attempt came back to haunt the hosts with only minutes left in the first half, as Williams got his second when he received the ball on the right-hand side of the box, with the Ghanaian international opting to take a shot from a tight angle to beat Livaković at his near post.
The start of the second half didn’t see any change in the aggression in the match, with both sides continuing to battle for possession, although Athletic were the ones creating chances as Guruzeta and Álex Berenguer both spurned opportunities for the visitors.
Just as it looked like the hosts might find a way back into proceedings, they received another setback, as Müldür received a second yellow for a late challenge on Williams to all but kill their momentum.
While they might have pushed the visitors all the way to FT, it is ultimately another setback for Fenerbahçe as they will need to avoid defeats in their last two UEL league phase games to progress to the knockouts.
Meanwhile, Athletic move top of the table for at least 24 hours, as an automatic place in the last 16 looks all but certain for Ernesto Valverde and his men.
Flashscore Man of the Match: Iñaki Williams (Athletic Club)