For Mikel Arteta, it was a timely reminder of just how fine the margins can be. With his team leading 1-0 thanks to Kai Havertz’s sublime first-half lob, the Arsenal manager could have been forgiven for thinking his team were on course for a third straight victory to start the season after signing surprise loanee Raheem Sterling from Chelsea on deadline day.

However, with just four minutes of the second half played, disaster struck as Declan Rice was sent off in a bizarre moment when he collided with Brighton’s Joël Veltman while attempting a free-kick. João Pedro equalised for Fabian Hürzeler’s side, who kept pace with Arsenal and maintained their unbeaten record despite both teams having chances to take all three points in the closing stages.

But it was Rice’s red card – the first of his Premier League career – that proved to be the turning point of the match, with referee Chris Kavanagh leaving the field amid boos from the home crowd and questions from Arteta for his failure to keep the fiery contest under control.

There was an extra loud cheer before kick-off when Sterling’s name was announced, along with fellow new signings Mikel Merino and goalkeeper Neto. Arteta had hoped to keep the Spanish midfielder on the bench until he suffered an unfortunate shoulder injury in his first training session on Thursday and had to settle for a place in the stands. The only change from Arsenal’s win at Aston Villa last week was the signing of Leandro Trossard for Gabriel Martinelli.

Several of Brighton’s newcomers have also been sidelined, with Turkish defender Ferdi Kadioglu injured in training on Friday. That meant Jack Hinshelwood remained at left-back, and he needed a pep talk from Hürzeler after being battered by Bukyao Saka for 15 minutes as a dejected James Milner was forced off. With new central midfielders Matt O’Riley and Mats Wieffer also unavailable following their summer arrivals, Brighton have had to call on substitute Yasin Ayari to fill the void alongside 20-year-old Carlos Baleba.

The visitors tested David Raya when Yankuba Minteh headed Joao Pedro’s deep cross towards goal. Despite taking a poor tackle from Minteh, Martin Ødegaard continued to direct Arsenal’s energetic pressure. Brighton were slowly finding their rhythm and an attack started by Baleba eventually ended with Kaoru Mitoma’s volley just wide of the post.

But they had no one to blame but themselves when they fell behind seven minutes before half-time. Lewis Dunk was far too casual in handling a hopeful ball forward and inexplicably dived away instead of heading the ball. Saka saw his chance, spun behind him and then played in Havertz to execute a brilliant lob over Bart Verbruggen. Hürzeler’s frustrations boiled over shortly afterwards when he was shown a yellow card for protesting that a yellow card given to Rice for a charge on Veltman should have resulted in a more severe punishment.

Hinshelwood had to block Rice’s shot on goal after a beautifully flowing backheel from Jurrien Timber as Arsenal started strongly after the break. However, the England midfielder’s afternoon took a dramatic turn shortly afterwards when he was sent off after receiving a second yellow card following a bizarre incident with Veltman. The Brighton defender had been awarded a free kick but Rice attempted to clear the ball and was himself kicked by Veltman at the same time, with Kavanagh ruling that only the Arsenal midfielder deserved a yellow card. The home fans were understandably angry and their mood towards the officials was only darkened when Dunk atoned for his mistake by playing a straight ball through the middle of Arsenal’s defence to Danny Welbeck. His shot was saved but Joao Pedro gobbled up the rebound – the first goal Arsenal have conceded this season.

Arteta’s response was to bring on Riccardo Calafiori and switch to a five-man defence, with Ødegaard just unable to pick out the Italian defender for a chance when he made a long-burst run down the left flank. It was all hands on deck as Brighton continued to pile on the pressure, although Havertz was denied by Verbruggen’s outstretched leg before Saka failed to capitalise on another decent chance on the break.

Georginio Rutter and Baleba both shot wide after Gabriel blocked the latter’s shot with his stomach. But Arsenal held on and at least had the consolation of a point in a game they seemed destined to win.