Arsenal won the Community Shield after a penalty shootout victory over Chelsea at Wembley.
Sead Kolasinac scored a dramatic equaliser in normal time – immediately after the Blues were reduced to 10 men.
Victor Moses opened the scoring in the at Wembley inside 60 seconds of the second-half but they lost Pedro to a red card for a poor challenge on Mohamed Elneny.
And Arsenal made them pay as Kolasinac headed in at the back post.
The encounter went to penalties as both Thibaut Courtois and Alvaro Morata missed before Olivier Giroud scored the winning spotkick.
The Gunners went closest to scoring during the first-half through new signing Alexandre Lacazette, who hit the post.
Arsenal have lost skipper Per Mertesacker to injury though, with the German suffering a blow to his head.
Late in the first half, Willian was booked for diving by referee Bobby Madley after a challenge from Hector Bellerin.