This was some response to charges of being goal shy. Arsenal knew they needed to discover a cutting edge abroad and duly located it at the home of the Champions League’s form team. Their best European away performance of the past half-decade was beautifully timed, furthering the sense that they are back to their old selves and making swift passage to the knockout stage look significantly more realistic.
When Leandro Trossard completed the scoring it felt a trick of the mind that Sporting had blown Manchester City away on the same pitch this month. It was hardly an obvious venue for Arsenal to cut loose and score five times on the continent for the first time since October 2008. Beyond a 15-minute spell after the interval, when Gonçalo Inácio put a dent in their three-goal lead and the home side briefly looked capable of causing serious alarm, they were in complete command and superior in every department.
