Mikel Arteta's champions needed just 23 seconds to take control, with Myles Lewis-Skelly splitting the City defence with a superb pass for Riccardo Calafiori. The Italian kept his composure to slot past new City goalkeeper Gianluigi Donnarumma.
It was the fastest Community Shield goal since 1968 and immediately exposed the uncertainty surrounding a Manchester City side beginning life under new manager Enzo Maresca following Pep Guardiola's departure.
Arsenal doubled their advantage in the 27th minute when Martin Odegaard delivered a cross towards the far post. Christos Tzolis, one of the Gunners' major new recruits, headed the ball back across goal for Kai Havertz to score with a downward header.
Tzolis was at the heart of Arsenal's third goal shortly after half-time, completing an impressive debut with his second assist. His pass released Odegaard inside the box and the Arsenal captain left Donnarumma wrong-footed before calmly finishing.
The result handed Arsenal their second trophy in four months and their 18th Community Shield success, although Arteta will be more interested in what the performance says about his side's prospects of retaining the Premier League crown.
Arsenal's defence was particularly impressive after conceding eight goals during pre-season. David Raya denied Erling Haaland before Myles Lewis-Skelly and Ben White combined to block the rebound and a subsequent Jeremy Doku effort.
City, meanwhile, struggled to create a sustained threat. Haaland was withdrawn after an ineffective display, while 116 million pounds signing Elliot Anderson also failed to make an impact. Rodri's absence was keenly felt as City's midfield lacked the control that had become a hallmark of Guardiola's era.
Tzolis' performance was a major positive for Arsenal, with the Greek becoming the first Gunners player since Willian in 2020 to provide two or more assists on his debut.
The victory also showcased Arsenal's summer additions, with Bruno Guimaraes, signed from Newcastle for 75 million pounds, settling into midfield impressively alongside the lively Tzolis.
Arteta has repeatedly stressed that his players remain hungry for more silverware after finally ending their long wait for the Premier League title. Their Champions League final defeat by Paris Saint-Germain in May has also provided additional motivation.
Maresca now faces a significant challenge to reduce the gap between City and Arsenal. City finished seven points behind the champions last season and have not won the Premier League since 2024.
Arsenal begin their title defence against promoted Coventry on August 21, while City host Bournemouth two days later. If the Community Shield is any indication, the champions have no intention of surrendering their position at the top without a fight.
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Mikel Arteta hailed his Arsenal team for laying down a marker ahead of the Premier League season after trouncing Manchester City 3-0 to claim the Community Shield in Cardiff.
Mikel Arteta has moved to reassure Arsenal fans over his future at the club, insisting there is no reason for concern despite having only 12 months remaining on his contract.
