Donny van de Beek marked his first Manchester United appearance since January with a superb volleyed winner as Erik ten Hag's side beat Lyon 1-0 at Murrayfield.
Chelsea have signed Lyon right-back Malo Gusto for £26.3m, with the 19-year-old spending the rest of the season back in France on loan.
Arsenal opened their Champions League group campaign with a 5-1 thrashing of holders Lyon in France.
Real Madrid beat city rivals Atletico but racist chanting directed at Vinicius Jr outside the Metropolitano marred the derby.
West Ham have completed the signing of Brazil international midfielder Lucas Paqueta from Lyon for a club-record fee of around £51m.