Arsenal edge one point clear of Liverpool, who face Manchester United on Sunday, and champions Manchester City at the top of the table.
Bukayo Saka opened the scoring from the penalty spot before the much-maligned Kai Havertz slotted in his fifth goal in his last nine Arsenal games to continue silencing his critics.
Leandro Trossard came off the bench to haunt his old club with a cool chip over Bart Verbruggen for the third five minutes from time.
“We are older. We went trough a lot of moments together and the chemistry you build within the team,” said Arteta on what was different from a year ago when City stormed clear down the final straight.
“We signed some tremendous players as well which helps. The squad is healthy and the momentum is good.”
Brighton had not lost at home in 14 games in all competitions stretching back to September, but they had not met a side of Arsenal’s class on that run.
They have now won 10 and drawn one, away to Manchester City, of their last 11 league games.
Saka had been nursing an injury in recent weeks and was rested for Wednesday’s 2-0 victory over Luton.
But he marked his return with his 17th goal of the season after Gabriel Jesus had been tripped inside the box on 33 minutes.
“I was struggling but as long as I have two legs I’m going to give everything and want to be out on the pitch,” said Saka.
“We’re all buzzing, we know the win takes us back on top. We’re building momentum.”
Arsenal have now kept five consecutive clean sheets on the road in the Premier League and their desperation not to concede was summed up by the wild celebrations by Gabriel and his teammates after the Brazilian made a late block with the game already settled.
“The desire and love for defending from the players is there,” added Arteta.
“You saw the reaction of the teammates with Gabi’s block. That is them, not me, that’s the spirit within the team.”
Julio Enciso came closest to a response for the Seagulls with a curling effort from outside the box in the first half that David Raya did well to turn behind.
Arsenal were less threatening after the break but scored the all-important second goal when Jorginho got to the by-line and his cross was tapped in at the near post by Havertz.
The German international then turned provider for the third as he set Trossard galloping clear in behind the Brighton defence to score on his first return to the Amex since leaving for the Emirates in January 2023.
City were 4-2 winners over Crystal Palace earlier on Saturday and now the pressure is on Liverpool to respond to their title challengers when they return to Old Trafford seeking revenge.
Just three weeks ago Jurgen Klopp’s men were beaten 4-3 by United in a thrilling FA Cup quarter-final.
© Agence France-Presse
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