Manchester United 1 Arsenal 1
United win 4-3 on penalties
Rookie goalkeeper Tim Howard emerged as Manchester United's Community Shield match-winner as Arsenal suffered the ignominy of not only defeat but also an unwelcome half-century for Arsene Wenger.
The American, who was preferred to Fabien Barthez in the starting line-up, flung himself to deny both Giovanni van Bronckhorst and Robert Pires in a penalty shoot-out.
Arsenal, who had seen Francis Jeffers become the 50th player to be sent off since Wenger took charge of the club in 1996, were therefore undone by a former basketball player.
However, after a match in which they were fortunate to only have one player sent off, they had rather more cause to reflect upon their own indiscipline.
The Gunners may have worked hard to improve their disciplinary record over recent years but they still managed to incur five dismissals last season.
And while Jeffers may be Thierry Henry's deputy at Arsenal, his dismissal still means a three-match ban, just when his side need to make a strong start in their bid to dethrone United.
Relations between the two clubs were hardly improved when Arsenal accused Ole Gunnar Solskjaer of reneging on a verbal promise of support in Sol Campbell's appeal against his red card in last season's Highbury tussle.
However, Jeffers, a second-half substitute for Henry, was sent off for kicking out at Phil Neville while the United defender was lying on the ground.
And Campbell was himself fortunate not to be sent off again in Cardiff, as was Ashley Cole in an earlier clash as he became one of five players to be booked on either side.
The match itself had been a lively affair, with Mikael Silvestre's early header quickly cancelled out by a superb free-kick from Henry.
The late drama should not detract from a supreme display from Paul Scholes, who ensured the summer departures of David Beckham and Juan Sebastian Veron were no problem for United on this occasion.
The champions served notice that Arsenal and, indeed, Chelsea, Liverpool or Newcastle, must overthrow the established order if they are to challenge for the title.
With Phil Neville and Cole booked in the first two minutes, this was always going to be a highly competitive fixture.
United struck first on 15 minutes, with Ryan Giggs' low corner being flicked on by Roy Keane and Silvestre arriving unmarked to head home.
That was a rude awakening for Arsenal's own new goalkeeper Jens Lehmann, although Kolo Toure otherwise gave an encouraging display at centre-back in the absence of Martin Keown in the position that is his team's Achilles heel.
Not that Howard was afforded any more protection by his undermanned wall when Henry unleashed a curling free-kick from 30 yards out.
That was awarded for what looked a well-timed tackle by Nicky Butt on Patrick Vieira, although referee Steve Bennett was in a rather more forgiving mood when Cole escaped his second caution for a kick on Solskjaer.
Solskjaer thrived in Beckham's absence and, on at least three occasions, Cole failed to cut out searching through-balls to him from Scholes, with the Norwegian volleying one against the side-netting.
With Wenger replacing all but Vieira out of his midfield and attack, he was clearly determined to keep his players fresh for the main event.
In contrast, Scholes looked close to the peak of his powers, giving Giggs a half-chance which he lobbed wide, while Eric Djemba-Djemba - on his debut - fired just over.
However, there was no warning of the rash moment in which Jeffers lost his cool and kicked Neville after what the Everton man felt was an unfair challenge.
When Djemba-Djemba then followed through with a studs-first challenge on Campbell, the England defender was fortunate not to follow his team-mate off the pitch as he also responded in anger.
Van Nistelrooy flashed a shot wide, while Howard was just off his line in time to deny Sylvain Wiltord, meaning that penalties were required.
After Scholes, Edu and Rio Ferdinand had all scored, Howard flung himself to his right to deny van Bronckhorst.
That save was eclipsed by Lehmann's stunning block from van Nistelrooy but with Wiltord, Solskjaer, Lauren and Diego Forlan all scoring, the pressure was on Pires.
The Frenchman's effort was firm but Howard was equal to it. The pre-season focus at Old Trafford may all have been on departures, but this was one summer arrival making an immediate impression.