Arsenal suffered a double injury blow during their Europa League clash with Sporting as defenders William Saliba and Takehiro Tomiyasu departed the field after just 20 minutes.
The Gunners went ahead inside 20 minutes with Granit Xhaka finishing coolly after Gabriel Martinelli's initial shot had been saved by Antonio Adan.
Former Middlesbrough and Fulham keeper Mark Schwarzer told BBC Radio 5 Live: 'Looks devastated does Takehiro Tomiyasu. It was just a really unfortunate fall from him as he got his studs stuck in the ground.
'But now there is an opportunity for Ben White to show Gareth Southgate what he is missing out on.