A second-half goal from Joao Pedro saw Brighton come from behind to draw after Arsenal had Declan Rice sent off in an entertaining game in north London.
It looked as though the Gunners were going to continue their perfect start to the season when Bukayo Saka played through Kai Havertz, who lobbed Bart Verbruggen in the Brighton goal for the 38th-minute opener.
However, the game completely changed after Declan Rice was dismissed for a second yellow card in the 49th minute for delaying a free-kick being taken by Joel Veltman.
The Seagulls defender could also feel lucky to have got away without picking up a card himself.
Brighton piled on the pressure after that point and drew level in the 58th minute when Yankuba Minteh’s shot was parried into the path of Pedro by David Raya and the Brazilian striker slotted the ball under the keeper.
Havertz then had a good chance to win the game when through on goal, but his effort was saved by Verbruggen, before Seagulls substitute Yasin Ayari had an effort saved by Raya late in the game.
Brighton continued to push for a winner and brought on new £39.5m signing Georginio Rutter as they looked for a magic moment, but he mistimed a header as they could not find the decisive strike.
