Sunderland host Dutch side AZ Alkmaar in their first European fixture since 1973-74, marking a landmark return to continental football after an unexpected seventh-place Premier League finish secured them a place in this season's expanded Europa League. The club's only prior European foray came 52 years ago, when they lost 2-1 at home to Sporting in a two-legged tie before falling 2-0 away, ending that campaign; this time they are guaranteed eight league-phase fixtures as part of football's revamped 36-team format.

Elsewhere on the opening matchday, seven-times European champions Milan host Benfica in one of the standout ties, while Lyon travel to Anderlecht and Bayer Leverkusen welcome Slovenia's Celje in their first outings of the campaign. The competition builds towards a final in Frankfurt, with Sunderland's clash against AZ, mainstays of the Europa and Conference Leagues, seen as an early gauge of their readiness for the demands of a long European run.