Arsenal commenced their UEFA Champions League campaign with a 2-0 victory over Athletic Bilbao, despite initial struggles with creativity and a significant number of key players sidelined due to injury. Manager Mikel Arteta faced a formidable challenge, with captain Martin Odegaard, Ben White, Gabriel Jesus, Kai Havertz, and Bukayo Saka all unavailable for the trip to Spain. William Saliba, however, had recovered from an ankle issue and was available, though Cristhian Mosquera continued his impressive form.

The first 45 minutes of the match saw Arsenal lacking their usual attacking flair, primarily due to the absence of creative forces like Saka and Odegaard. Champions League debutants Eberechi Eze and Noni Madueke struggled to make a significant impact from wide positions. Declan Rice, returning to the starting XI after being rested, had an unusually difficult night, receiving an early yellow card and failing to shoulder the creative burden. Viktor Gyokeres, despite his relentless runs, failed to convert several chances, including a header from a superb Jurrien Timber cross and another from a Declan Rice free-kick. Gyokeres also sustained a nasty head injury after a clash with teammate Gabriel during a free-kick, requiring a Terry Butcher-style headband to continue playing.

Arsenal's defense, however, remained resolute, providing a stable foundation. David Raya demonstrated good positioning and distribution, while Jurrien Timber impressed with defensive solidity and attacking runs. Gabriel, wearing the captain's armband, offered a calming presence, and Cristhian Mosquera, a summer signing, seamlessly filled in for William Saliba. Riccardo Calafiori also made a strong appearance with well-timed tackles and marauding runs.

The turning point came in the second half with Mikel Arteta's tactical substitutions. In the 65th minute, Leandro Trossard replaced Viktor Gyokeres, and in the 71st minute, Gabriel Martinelli came on for Eberechi Eze. These changes had an immediate and decisive impact. Gabriel Martinelli, who had been out of sorts, scored a mere 36 seconds after his introduction, silencing doubts and breaking the deadlock. His close control and blistering pace proved crucial on the left flank. Martinelli then turned provider, assisting Leandro Trossard for Arsenal's second goal in the 87th minute, sealing a winning start to their European campaign.

The victory, inspired by the bench, allowed Arsenal to return home with a much-needed feel-good factor, despite acknowledging the poor performance for large periods. The defensive stability and the clinical finishing provided by the substitutes ultimately overcame a dogged Athletic Bilbao side, whose fans passionately supported their team after an 11-year absence from Europe's elite competition. The win, however, came at a cost, with Gyokeres and Mikel Merino picking up head gashes, adding to Arsenal's injury concerns ahead of their crucial match against Manchester City.