17' CHANCE! Smith Rowe drops deep to receive the ball and plays it short to Cedric before charging in behind. Cedric pings it over the top and Otamendi fails to make contact with an acrobatic attempt at a clearance, but Leite sprints off his line to head clear!
15' Benfica are settling into the game and are starting to press higher and condense the centre of the pitch, attempting to slow the game down on the rare occasions they do have the ball.
13' Waldschmidt is presented with a half-chance just inside the Arsenal box and he snatches at the shot, seeing it take a deflection and spin well wide of the target.
11' Benfica briefly have the ball, but the Gunners swarm forward to press high and prevent their progression. Xhaka is a little overzealous, however, and concedes a free kick.
9' Arsenal are looking for incisive passes in behind, but it's not come off just yet. Saka is caught marginally offside from a David Luiz pass down the right and then Xhaka's attempted ball is just cut out by Vertonghen.
7' Arsenal have completely dominated possession in the opening stages, enjoying over 85% of the ball thus far - with plenty of it coming high up the field.
5' The Gunners have maintained their positive start and have Benfica pinned back. Bellerin drives to the byline and tries to fire a low ball in, but it's diverted behind by Vertonghen.
3' Arsenal have started on the front foot but their early adventure has been hampered by the offside flag, raised twice against Aubameyang. Both calls were very tight, but the decisions go Benfica's way this time.
1' The referee blows his whistle and gets the game underway!
However, Arsenal have faced four other Portuguese opponents in European competition and beaten them all (Sporting CP, Porto, Sporting Braga and Vitoria Guimaraes).
Benfica and Arsenal met in the last 16 of the 1991/92 European Cup, with Benfica winning 4-2 on aggregate (1-1 home, 3-1 away); these are the only two meetings between the teams.
Meanwhile, Arsenal manager Mikel Arteta makes no changes to the side he named in the Gunners' 4-2 victory over Leeds United in the Premier League on Sunday. Midfielder Thomas Partey misses out as he recovers from a thigh injury, but left-back Tierney is fit enough to make the bench.
Benfica boss Jorge Jesus makes three changes to the side that started in their disappointing 1-1 draw with Moreirense last time out. Everton, Rafa and Seferovic all drop to the bench, with Verissimo, Pizzi and Waldschmidt taking their places in what appears to be a shift to a back three.
Arsenal substitutes: Willian, Alexandre Lacazette, Nicolas Pepe, Mat Ryan, Calum Chambers, Kieran Tierney, Mohamed Elneny, Gabriel Martinelli, Karl Hein, Eddie Nketiah, Rob Holding, Pablo Mari.
Arsenal XI (4-2-3-1): Bernd Leno; Hector Bellerin, David Luiz, Gabriel Magalhaes, Cedric Soares; Dani Ceballos, Granit Xhaka; Bukayo Saka, Martin Odegaard, Emile Smith Rowe; Pierre-Emerick Aubameyang.
Benfica substitutes: Gabriel Pires, Pedrinho, Haris Seferovic, Everton, Chiquinho, Nuno Tavares, Franco Cervi, Joao Ferreira, Rafa, Odisseas Vlachodimos, Mile Svilar, Gilberto.
Benfica XI (3-5-1-1): Helton Leite; Lucas Verissimo, Nicolas Otamendi, Jan Vertonghen; Diogo Goncalves, Adel Taarabt, Julian Weigl, Pizzi, Alejandro Grimaldo; Gian-Luca Waldschmidt; Darwin Nunez.
Benfica's failure to win their group - finishing second behind Rangers despite going unbeaten - has resulted in a tough draw for the Portuguese giants against Arsenal, who won all six of their group games. The game is taking place at the Stadio Olimpico in Rome due to coronavirus restrictions, with the second leg to be held in Greece.
Hello and welcome to our LIVE coverage of the Europa League round of 32 first leg clash between Benfica and Arsenal.