Arsenal's perfect start to their Premier League title defence was halted in crushing fashion as Brighton thrashed Mikel Arteta's side 3-0 at the American Express Stadium.

The champions were comfortably off the pace on the south coast as Brighton – who are the Premier League's leading scorers in 2026-27 – climbed to third in the table with a ruthless display.

Pascal Gross, Charalampos Kostoulas and Chema Andres were on the scoresheet for Fabian Hurzeler's Seagulls, and the final scoreline arguably flattered Arsenal, if anything, as Pascal Struijk, Matt O'Riley and Malick Yalcouye all went close to adding a fourth goal.

Arsenal did not settle at all in the early stages, with Brighton's high press causing several nervy moments for the Gunners as they attempted to play out from the back.

One of those instances saw David Raya pass straight to Yasin Ayari, with only a strong recovery challenge from Declan Rice denying him a clear shot at goal, soon after the Arsenal goalkeeper had dived to his right to tip Kostoulas' drive around the post.

And Brighton deservedly took the lead in the 31st minute. Gross was afforded far too much time and space 20 yards out, slightly to the right of the D, and his shot thumped off the base of the near post and in.

It was a similar story for Brighton's second goal in the 45th minute, as both Rice and Gabriel Magalhaes backed off Kostoulas, who picked out the bottom-left corner from 25 yards.

Charalampos Kostoulas. What a player.  pic.twitter.com/GxOGBhS2aE

— Brighton & Hove Albion (@BHAFC) September 19, 2026

Arteta would have expected a much-improved showing after half-time, but he got nothing of the sort as Brighton struck again just before the hour mark.

Gross swung a deep corner delivery in from the left, and with Raya rooted to his line, Chema towered above Gabriel and Martin Odegaard to head home on his first Premier League start, aided by a touch off the near post.

Arsenal almost conceded another set-piece goal when Struijk stole a march on Raya and nodded wide, while Kostoulas also had a penalty appeal waved away following a desperate lunge from Gabriel.

Kai Havertz squandered Arsenal's only real chance to provoke some anxiety among the home fans, and Brighton had several opportunities to make the scoreline even more handsome late on.

Georginio Rutter turned wide from Maxim De Cuyper's cross-shot and O'Riley was thwarted by Raya following a glorious move, with Yalcouye striking the woodwork on the follow-up from the latter chance, with Arsenal fortunate to only lose by three.

Gross and Kostoulas shine as Brighton claim another big scalp

Brighton donned a one-off kit for Saturday's game to celebrate the club's 125th anniversary, and it is fair to say they marked the occasion in style. 

Happy 125th birthday to us… 

— Brighton & Hove Albion (@BHAFC) September 19, 2026

Arsenal had not been three goals down in any Premier League match since May 2023, when a 3-0 home defeat to – you guessed it, Brighton – all but ended their title ambitions for the 2022-23 campaign.

But the Seagulls made the champions look distinctly ordinary here, turning their 40.3% possession share into 17 shots, 1.33 expected goals and four Opta-defined big chances. The Gunners registered 11 shots, 1.58 xG and two big chances.  

Brighton's ability to outperform their underling figures was the result of some pinpoint finishing from outside the area, with both Gross and Kostoulas striking from range. Seven of the last 18 Premier League goals Arsenal have conceded have come from outside the 18-yard box, including three of four this campaign.

Gross has now scored in three consecutive games for Brighton for the very first time (in all competitions), while Kostoulas has twice as many goal involvements in 2026-27 (six) as he managed in the entirety of 2025-26 (three).

And this is the third consecutive season in which the Seagulls have beaten the reigning Premier League champions at home, having also overcome Manchester City in 2024-25 and Liverpool in 2025-26.