Arsenal suffered their first defeat of the season as they were stunned by Brighton, who put three past the champions at Amex Stadium.

On the back of fine wins over Coventry City and Manchester United, the Seagulls started the match in confident style.

The Gunners struggled to deal with the intensity shown by the hosts and Pascal Gross gave Brighton a 31st-minute lead with a shot from the edge of the box that went in off the post.

Arsenal, who had won their past nine league games and seven in all competitions at the start of this campaign, were not allowed to settle and looked uncharacteristically nervy on the ball.

They forced their best chance to equalise on a counter-attack just before half-time, but Bukayo Saka did not take the opportunity after the ball fell to him in the area following Martin Odegaard's deflected effort.

Just seconds after that missed opportunity, Brighton claimed their second goal as Charalampos Kostoulas was given too much space on the edge of the box to turn and fire past David Raya.

Mikel Arteta opted not to make any changes at half-time as he looked for a response from his side, but it didn't come as Chema Andres headed in Brighton's third 12 minutes into the second half from a Gross corner.

It was an 11th goal in the past week after five at Coventry and a 3-2 comeback success at Old Trafford to stun United in the Carabao Cup.

Defender Pascal Struijk, making his first Premier League start for Brighton since a summer arrival from Leeds, almost added a fourth from another corner, but headed wide under pressure.

Kai Havertz had a late opportunity to pull one back for Arsenal but shot straight at home keeper Bart Verbruggen when through on goal, while Matt O'Riley was denied at the other end by Raya.

The defeat left the defending champions second in the table on goal difference having played one game more than Manchester City, who host Sunderland on Sunday, while Brighton moved up to third and two points behind the leaders.

Arsenal analysis: Wake-up call for below-par Gunners

Arsenal's season had been going perfectly until this heavy loss - against a side who beat them by the same margin at Emirates Stadium in 2023.

The Gunners had conceded just one goal in the league this term during their impressive winning streak, but the performance against the Seagulls was far from the standards Arteta has demanded from his side.

Bruno Guimaraes was given his first league start, but the Brazilian failed to click with Declan Rice and Odegaard in the middle of the pitch.

Arteta regularly makes a big point of wanting his side to be physically dominant in games, but the Gunners were beaten in duels all over the pitch as Brighton took control.

Keeper Raya, usually so dependable with the ball at his feet, looked unsure at times due to the pressure from the hosts, with Arsenal also registering just two shots on target which shows just how much they struggled in possession.

Arteta will also be disappointed with how his side conceded the three goals, with his defenders allowing far too much space and time for shots from the edge of the area for the first two, and the third coming from a set-piece.

This defeat won't define Arsenal's title defence, but will be a wake-up call as the international break starts.

Brighton analysis: Fearless Seagulls rewarded for attacking approach

Brighton came into this match as the league's top scorers and did not disappoint with their attacking mindset.

But they worked hard in possession and when battling for the ball to deny Arsenal the space in which they thrive.

Diego Gomez on the wing did an excellent job of keeping Riccardo Calafiori quiet, while Kostoulas caused problems for the Gunners backline throughout.

The 19-year-old Greece international deserved his excellent goal, which was his third in successive games, as he looks to show he can step up to be Brighton's main striker following Danny Welbeck's summer departure to Chelsea.

But he was well supported by his team-mates, with Spaniard Andres marking his first league start with a first goal for the club.

And then there was the 35-year-old Gross, who has rolled back the years with his performances so far.

The German, who rejoined the club in January from Borussia Dortmund, was again the conductor of Brighton's play and now has four goals in his last five games.

Fabian Hurzeler's side are packed with young talent and have a fearless approach that will cause problems and concern for any side - as both Manchester United and Arsenal found out over the past week.