- Kaoru Mitoma (65')
- Evan Ferguson (77')
- Bukayo Saka (2')
- Martin Ødegaard (39')
- Eddie Nketiah (47')
- Gabriel Martinelli (71')
Bukayo Saka opened the scoring in the second minute while Martin Odegaard, Eddie Nketiah and Gabriel Martinelli all scored to ensure a fairly routine win for Mikel Arteta's side despite goals from Kaoru Mitoma and 18-year-old Evan Ferguson and some nervy moments late on.
"Big win, against a really good side," Arteta told Sky Sports. "We had big moments, especially attacking open spaces, we were ruthless. We were really clinical.
"We had some great moments and then as well there were some moments where we had to dig in and suffer because they put you in trouble, they are a really good side."
Odegaard doubled Arsenal's lead with a bouncing left-footed finish from a corner in the 39th minute which ensured his team went into half-time in a comfortable position.
And they made their dominance felt three minutes after the break when Nketiah prodded past Sanchez after the Brighton keeper got a hand to a shot from Martinelli.
Arsenal looked to be cruising to victory, but Mitoma gave them food for thought in the 65th minute when he was sent through by Pascal Gross and sent a low finish past Aaron Ramsdale.
Martinelli restored Arsenal's cushion when he dashed through in the 71st minute before slotting past Sanchez following an incisive pass from Odegaard, before Ferguson became Brighton's youngest Premier League goalscorer.
A right-footed finish from Mitoma in the 89th minute caused a late scare for Arsenal, but the goal was ruled offside after a VAR review.
Arsenal end 2022 with 43 points from 16 games, seven points more than champions Man City and nine ahead of Newcastle, who they host on Tuesday.
"We have to play every game, now we have to focus again, review the match -- a lot of things that we done really well, a lot of things still to improve," Arteta added.
"And take those ones into the next match, take the same energy, momentum. We're going to play in front of our crowd, it's going to be a really special game again and looking forward to it."
- Anthony Taylor
|Brighton & Hove Albion||5||4||0||1||+8||12|
|West Ham United||5||3||1||1||+3||10|