A seething Mikel Arteta admitted that he was “amazed about how inconsistent the decisions can be” after Declan Rice was sent off as Arsenal dropped their first points of the new season against Brighton.

Arsenal had looked on course to maintain their 100% start to the new campaign when Bukayo Saka pounced on a mistake by Lewis Dunk to set up Kai Havertz. But an incident early in the second half when Rice, who had never been sent off before in his career and will now miss the north London derby against Tottenham after the international break, was shown a second yellow card by referee Chris Kavanagh after being deemed to have obstructed Joël Veltman from taking a free-kick altered the momentum of the game entirely.

João Pedro went on to equalise and maintain Brighton’s unbeaten start under Fabian Hürzeler. But Arteta said that he had been stunned by Kavanagh’s decision not to take any action against Veltman for making contact with Rice and with another incident in the first half when Pedro kicked the ball away.

“I was amazed. Amazed, amazed, amazed because of how inconsistent decisions can be,” he said.

“In the first half, there are two incidents and nothing happens.

“Then, in a non-critical area, the ball hits Declan, he turns around, he doesn’t see the player coming and he touches the ball.

“By law, he can make that call, but then by law he needs to make the next call, which is a red card so we play 10 v 10. This is what amazed me. At this level it’s amazing.”

Rice said later he was “shocked … I think you could see that on my face. But this is the laws of the game. If you touch the ball even a little bit it’s a red card after my challenge in the first half. It was tough, it was harsh but I have to move on from it.”

Hürzeler, the 31-year-old who replaced Roberto De Zerbi in the Brighton dugout this summer, felt Kavanagh had made the right decision. “For me it was a clear red card,” he said. “He shoots the ball away – it’s wasting time.”

Arsenal still had an opportunity to take all three points but Havertz and Saka both spurned late opportunities and Arteta’s side now face the prospect of a trip to Tottenham without Rice or new signing Mikel Merino, who injured his shoulder in his first training session this week. “This is what happens. We have to adapt to that context,” said the Arsenal manager.

“That’s why we have other players that can fulfil that [role] and give that opportunity to somebody else.

“But the team reacted to what we had to do playing at home with 10 men. We didn’t want to be so deep defending like this, but we read the game and we played the game that we had to play and we should have got rewarded.”