Reigning champions Manchester United open new season with win
Reigning champions Manchester United started the new Premier League season with a stylish 4-1 win at Swansea City.
Netherlands striker Robin van Persie scored twice for United, who had David Moyes in charge for the first time following the retirement of Sir Alex Ferguson.
There were wins for Fulham, Southampton and West Ham United.
England striker Danny Welbeck also scored two goals for Manchester United, with new £12m signing Wilfried Bony getting Swansea's consolation.
Arsenal, who took the lead through Olivier Giroud, were booed off the pitch as Christian Benteke grabbed two goals and Antonio Luna added a third for Villa.
England forward Daniel Sturridge, 22, scored Liverpool's winner at Anfield as Stoke boss Mark Hughes made a losing start in his first game.
Martinez, who was in charge of relegated Wigan last season, saw Ross Barkley and Seamus Coleman score after Steven Whittaker gave Norwich the lead.
Rickie Lambert, who scored the winning goal against Scotland on his England debut on Wednesday, netted a last-minute penalty to earn Southampton a 1-0 win at West Brom.
Pajtim Kasami's first Fulham goal secured three points at Sunderland, while Joe Cole and Kevin Nolan scored in each half as West Ham United overcame newly promoted Cardiff 2-0.