Gunners boss Mikel Arteta opted to stick with the same starting XI that cruised to a 4-2 victory over Leeds United at the weekend. Meanwhile, Benfica switched to a back five to contain the Premier League giants’ wide play.
Despite Arsenal’s large spell of possession and constant probing, the first half ended goalless.
Benfica finally broke the deadlock against the run of play in the second half when Emile Smith Rowe handled the ball inside the box while trying to block Diogo Goncalves' cross. Striker Pizzi calmly converted the penalty to secure his seventh goal in the Europa League.
However, Benfica's lead barely lasted two minutes as Arsenal came storming back with an equalizer. Cedric Soares drilled in a low cross from the byline, which was neatly tucked home by Bukayo Saka from close range.
Arsenal continued to move forward in search of the winning goal. However, when a glorious opportunity was presented to Pierre-Emerick Aubameyang, he failed to keep a cool head and dragged his shot wide off target.
Benfica held on tight to the draw, knowing that a larger goal advantage for the visitors would be a much harder task to overturn in the second leg.
The return leg is scheduled to take place in Athens next week, but Arsenal will first face Premier League leaders Manchester City this weekend.
Here are the Arsenal player ratings from their game against Benfica:
Arsenal player ratings against Benfica
Bernd Leno - 6/10
The Arsenal shot-stopper had little to do during the match but made a couple of routine saves. There was little to be done about the Benfica goal as it came via a penalty.
Hector Bellerin - 6.5/10
The Spaniard performed brilliantly down Arsenal's right flank as he constantly linked up with Bukayo Saka. He would have registered an assist on the night if not for Pierre-Emerick Aubameyang’s horror miss.
David Luiz - 7/10
The Brazilian was the leader at the center of the Arsenal defense. He commanded the backline and ensured that Benfica striker Darwin Nunez was kept at bay.
Gabriel Magalhaes - 7/10
Gabriel Magalhaes put in an assured performance against Benfica. He was eager to move forward and join the Arsenal attack but was also diligent in his defensive duties.
Cedric Soares - 6.5/10
Cedric Soares put in another solid shift for Arsenal. He occasionally raced into advanced areas while also keeping Diogo Gonçalves busy on the left flank.
The Portuguese grabbed an assist when he cut back a low cross into the path of Bukayo Saka.
Dani Ceballos - 7
Dani Ceballos always had the ball at his feet as he dictated Arsenal's pace and tempo all night. He stifled a few of Benfica’s breaks and linked up particularly well with Real Madrid loanee Martin Odegaard.
Granit Xhaka - 6
Granit Xhaka provided defensive cover in midfield but was found guilty of several misplaced passes.
The Arsenal midfielder made a goal-threatening mistake late in the first half when his poor pass fell to Benfica. His needless fouling prevented him from growing into the game.
Bukayo Saka - 7.5/10
Bukayo Saka has grown into a consistent performer for Arsenal. The 18-year-old grabbed Arsenal’s only goal of the night with a composed finish.
He linked up brilliantly with Hector Bellerin on the right flank, keeping the Benfica defenders on their toes the entire game.
Martin Odegaard - 7.5/10
This was the Real Madrid loanee’s best performance in an Arsenal shirt. He made several defense-splitting passes that threatened the Benfica defense while linking brilliantly with both his attackers and midfielders.
Emile Smith Rowe - 6/10
The Arsenal youngster was unfortunate to give away a penalty leading up to Benfica's opener. He showed a few flashes of brilliance but failed to make an impactful contribution. He was replaced by Gabriel Martinelli in the 77th minute.
Pierre-Emerick Aubameyang - 5.5/10
Pierre-Emerick Aubameyang was presented with glorious chances on either side of halftime but failed to make the most of them. He struggled to get into gear and was substituted for Nicolas Pepe in the 77th minute.
Kieran Tierney - 6/10
The Arsenal full-back made his return to action from injury in the 64th minute. He made a few darting runs forward and was solid down the left flank.
Nicolas Pepe - 6/10
Nicolas Pepe came on for the final 13 minutes of the game and put in a decent shift. The Ivorian fluffed a half-chance late in the game after he was played in by fellow substitute Tierney.
Gabriel Martinelli - 5/10
The Arsenal forward struggled to make an impact on the game as he was isolated throughout the night.
Mohamed Elneny - N/A
He replaced Dani Ceballos in the 90th minute and had too little time to make an impact.
Willian - N/A
The former Chelsea man was brought on for Odegaard towards the end of the game. He made no telling contribution.