Chelsea lost on penalties in the Community Shield match at Wembley, where Pedro was sent off.
Blues keeper Thibaut Courtois opted to take a spot-kick and blasted embarrassingly over, while record signing Alvaro Morata hit the outside of the post.
Olivier Giroud converted the winning penalty to give Arsenal another victory over Chelsea, having beaten them at the same venue in May’s FA Cup final.
The match finished level after 90 minutes. Victor Moses scored just a minute into the second half but Sead Kolasinac levelled straight after Pedro’s dismissal.
Chelsea went ahead when Arsenal only half-cleared Willian’s corner and Gary Cahill headed back into the penalty area, where Moses was unchallenged and able to steer the ball past former Blues keeper Petr Cech from close range.
But with nine minutes to go the Premier League champions were reduced to 10 men and saw their lead wiped out.
Pedro was red-carded for a nasty challenge on Mohamed Elneny and the resulting free-kick by Granit Xhaka was headed in by Kolasinac.
Earlier, Alexandre Lacazette hit the post during a first half in which Arsenal looked the more threatening.
Lacazette was lively for the Gunners and a move which started with him spraying the ball out to Hector Bellerin on the right ended with the French striker curling a right-footed shot against the woodwork from the near the edge of the penalty area.
Morata and fellow summer signing Antonio Rudiger both came on as second-half substitutes for Chelsea.
Morata, stretching to meet Willian’s ball over the top, sliced an effort high and wide shortly before Arsenal’s equaliser.
The Spanish striker was unlucky in the shoot-out, which was conducted under the new so-called ABBA format.
After Cahill emphatically tucked away Chelsea’s first spot-kick, Courtois and Morata missed whereas Arsenal scored all their penalties, with Theo Walcott, Nacho Monreal, Alex Oxlade-Chamberlain and Giroud all finding the target.
This post was last modified on 09/08/2017