The hosts needed a big performance after losing their past three domestic games, especially with a crunch trip to Premier League title rivals Manchester City coming up on Sunday.
They made a positive start, but the intensity soon dropped as Sporting settled into the contest, and Francisco Trincao had the first clear sight of goal when he fired well wide from just inside the box after 18 minutes.
Pedro Goncalves blazed over from a tight angle on the half-hour mark as the visitors continued to look assured, and the Emirates crowd grew increasingly edgy as half-time approached.
Geny Catamo fired a warning shot two minutes before the break when he met Maximiliano Araujo’s cross on the volley, only to see the ball clip the outside of the far post with David Raya beaten.
Eberechi Eze then sent an effort over the crossbar from 20 yards in the final act of a first half in which Arsenal failed to force Rui Silva into a save of note.
Sporting had scored 14 of their 20 UCL goals this season after the break, and they almost added to that tally when Araújo flashed a shot wide three minutes after the break.
Gunners manager Mikel Arteta responded by replacing former Sporting star Viktor Gyokeres with first-leg goalscorer Kai Havertz, and his side almost took the lead immediately as Noni Madueke raced into the box, but the winger was off balance as he fired into the side netting.
The nerves only increased as Arsenal struggled to find the goal to kill the tie, and Arteta was booked for protesting a decision midway through the half.
The Gunners had little margin for error, but they finished strongly as Sporting faded, with Leandro Trossard heading against the post from Max Dowman’s corner.
A UCL-high eighth clean sheet will give Arsenal a solid platform against last-four opponents Atlético Madrid, while they have now lost just one of their past 24 European games at the Emirates (W17, D6).
Meanwhile, Sporting’s wait for a first semi-final appearance in this competition continues, as they saw their winless run in continental away games against English sides stretch to 11 games (D6, L5).
Flashscore Man of the Match: Maximiliano Araujo (Sporting CP)
