Arsenal opened their Premier League account with a 1-0 win at Old Trafford, punishing Manchester United’s defensive frailties from a set piece.
Riccardo Calafiori reacted quickest to nod the ball over the line, handing Mikel Arteta’s side the lead.
New signings Bryan Mbeumo and Matheus Cunha impressed on debut, with Cunha striking the post and testing goalkeeper David Raya, but the finishing touch remained elusive.
Benjamin Sesko’s introduction after the break also failed to alter the outcome.
Arsenal, who struggled for attacking fluency, relied on their defensive organisation and depth from the bench to protect the lead.
Viktor Gyökeres and Martin Zubimendi endured difficult debuts, while substitutes Kai Havertz and Noni Madueke were introduced to steady the performance in the second half.