Going into a season in which he will be scrutinised like never before, this was pretty much the perfect way for Arsène Wenger to get things going. Back at Wembley and again facing Chelsea 71 days after defeating them in the FA Cup final, Arsenal have the feeling of silverware in their fingers once again via a victory carved out of the type of resilience they have long been accused of lacking.

There seemed no way back for Wenger’s side as this match entered its closing stages with Chelsea leading 1-0 through Victor Moses’s strike shortly after half-time. The champions had retreated, all but happy just to protect what they had and earn revenge for that defeat here in May. Previously that perhaps would have been enough, but not here. The men in red and white kept going, kept persevering, and on 82 minutes secured an equaliser via Sead Kolasinac’s close-range header.

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Cue an eruption of joy among the Arsenal supporters behind the goal into which the Bosnian, who arrived on a free transfer from Schalke in June, scored, and there was more to come after the penalty shootout that followed full-time. It was conducted under Fifa’s new ABBA system and ultimately Wenger’s men were the winners who took it all after Olivier Giroud hit the decisive spot-kick in a 4-1 victory.

As Arsenal celebrated, those within Chelsea’s ranks could only look on with collective glumness. After a sluggish start the champions had grown into proceedings and looked all set for a fifth Community Shield win, only for Pedro’s red card and Kolasinac’s immediate equaliser to change things completely. No one looked more frustrated than Antonio Conte, with this a less than ideal way to cap what has been a less than ideal summer for the Italian, one in which he has made known his frustrations over Chelsea’s slowness in the transfer market and had to deal with the protracted attempts to oust Diego Costa from the club.

The manager cut an agitated figure throughout this contest and not only expressed his regret over the result but his “disappointment” with the referee, Bobby Madley, for dismissing Pedro for the foul on Mohamed Elneny that led directly to Arsenal’s goal, and for not awarding his side a penalty on 35 minutes after Willian went down under a challenge by Héctor Bellerín. The subsequent yellow card shown to the Brazilian for diving only added to the Italian’s irritation.

“A lot of people told me the penalty was clear,” Conte said. “We have to respect referees’ decisions but sometimes these decisions make you angry.”

Not surprisingly, Wenger was far more upbeat. The Frenchman praised his side for winning “the trophy we really wanted to win” and, specifically, for not panicking after they went 1-0 down in a friendly that burned with intensity and good old-fashioned niggle throughout.

Along with Pedro’s red card, there were four yellow cards as well as the sight of Per Mertesacker leaving the field on 32 minutes with blood pouring from his head following a clash with Gary Cahill. The German could later be seen with stitches above his right eye, though Wenger said the injury was not serious enough to rule him out of the Premier League opener against Leicester City on Friday.

Mertesacker’s departure came after an impressive start by Arsenal. As was the case in the FA Cup final, they pressed Chelsea back and used possession quickly and efficiently through a 3-4-2-1 formation. Alex Iwobi and Danny Welbeck were particularly impressive in positions just behind Alexandre Lacazette, who was playing his most high-profile game for Arsenal since arriving from Lyon for £52.7m, with both testing Thibaut Courtois in the opening 10 minutes.

Chelsea were being suffocated and it did not help their cause that, when given the time and space to make an impact, their approach play was sloppy, with Michy Batshuayi an almost nonexistent presence as their lone centre‑forward until he was replaced by Álvaro Morata, the record signing, on 74 minutes.

Arsenal kept coming and nearly took the lead on 22 minutes when a Lacazette shot hit a post. They were well on top but that only added to the sense they had to strike sooner rather than later. Certainly having Alexis Sánchez on the pitch would have helped. Instead the Chilean watched as a non‑playing member of Wenger’s squad, having returned to first-team training only on Tuesday.

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Chelsea grew into the contest and before half-time Moses and Pedro both forced Petr Cech into making fine saves. Then came the penalty appeal and, while it could be argued Willian tumbled to the tuft all too easily as he surged into the Arsenal area, there is no doubt his left leg was clipped by Bellerín’s knee.

Chelsea were left indignant by Madley’s refusal to award a penalty but their mood improved on 46 minutes. Kolasinac, who had replaced Mertesacker, failed to clear a corner and after Cahill dropped the ball back into Arsenal’s area with a deft header Moses did the rest, lashing an unstoppable drive past Cech.

It was poor defending on Arsenal’s part but they did not cave in. Their central midfield partnership of Elneny and Granit Xhaka impressed in the closing stages and both played a part in the equaliser. The former was brought down via a studs-up tackle from Pedro and the latter delivered the free-kick from which Kolasinac, who generally impressed here, struck having drifted into enemy territory.

Penalties followed. Cahill scored for Chelsea with Theo Walcott and Nacho Monreal doing the same in succession for Arsenal. Then came the sight of Courtois stepping up to the spot. It was a gamble on Chelsea’s part and one that did not pay off after the 25-year-old lashed his drive over the bar.

Morata then caught the outside of Cech’s right post and, after Alex Oxlade‑Chamberlain made it 3-1, Giroud put the seal on a triumph that provided Arsenal with encouragement before what will be Wenger’s 21st full campaign in charge of the club. Maybe that new two‑year contract will work out well, after all.