Arsenal have reached the Europa League knockout phase, though with major injury concerns for Danny Welbeck.
Sporting ended the game with 10 men when ex-Barcelona defender Jeremy Mathieu was shown a straight red card after fouling Pierre-Emerick Aubameyang, who was clean through, although the hosts could not find a winning goal.
But the fixture was overshadowed by the injury to England international Welbeck, who was carried off on a stretcher.
The 27-year-old was hurt in the 25th minute when he jumped for a header and landed badly on his right ankle.
He received oxygen and had his leg in a protective brace as he was taken off the pitch, with up to 10 medical staff around him as he received treatment.
Some of his team-mates were also visibly affected by the incident.