Injury news
Mikel Arteta has confirmed that Martin Odegaard has not travelled after picking up a shoulder injury in the win over Nottingham Forest at the weekend.
On Bukayo Saka's hamstring injury, he said: "I think there are still quite a lot of things to go through.
"It’s very early to understand when and which week he’s going to be available.
"But he will certainly be pushing to be available as quickly as possible."
Ben White, Kai Havertz and Gabriel Jesus are also out.
For Athletic Bilbao, they are without their star man Nico Williams.
Get to know Athletic Bilbao
Arsenal's campaign begins with a trip to the San Mames Stadium in Bilbao tonight.
The 53,000-seater hosted the Europa League final last season as Spurs beat Man Utd 1-0.
It is set to be a raucous atmosphere in the Basque Country as the club have been absent from the Champions League for the last 11 years.
Ernesto Valverde is into his third spell as manager and this is his most successful yet.
He guided the club to Copa del Rey success in the 2023-24 season and a fourth place finish in LaLiga last term.
Athletic Bilbao are one of the most unique clubs in the world due to their "cantera" policy of only having players born within the Basque region of Spain and France.
Champions League LIVE
Welcome to SunSport's LIVE coverage of the Champions League.
Europe's biggest club competition is back tonight and the action starts at 17:45 BST as Arsenal travel to Athletic Bilbao.
The Gunners made the semi-final last year and, according to Mikel Arteta, were "much better" than eventual winners PSG in their 3-1 defeat to them on aggregate.
After the Arsenal match, it is a Champions League return for Tottenham as they welcome Villarreal to North London.
Thomas Frank has made a positive start to life at Spurs and can make it four wins from his last five games in charge.
There are six games this evening in total and you won't miss any of the action by sticking with us.