Substitute Alexandre Lacazette made an instant impact as Arsenal continued their resurgence by scraping a 1-0 win which prolonged Brighton's miserable home record.
Lacazette, dropped to the bench to accommodate recalled captain Pierre-Emerick Aubameyang, coolly bagged the second-half winner just 21 seconds after replacing Gabriel Martinelli.
The Frenchman's decisive 66th-minute strike made it back-to-back wins for the Gunners to move them nine points clear of the relegation zone and further ease mounting pressure on head coach Mikel Arteta.
Beleaguered Brighton remain just two points above the drop zone after failing to end their lengthy wait for a victory at the Amex Stadium.
The Seagulls, who lacked a cutting edge throughout, end 2020 with a solitary home win from 17 top-flight fixtures and with plenty of work to do in the new year.
Arsenal arrived on the south coast as the only team to have lost a league match here during the past 12 months following a 2-1 reverse in June but buoyed by Boxing Day's overdue 3-1 win over Chelsea.
Gunners boss Arteta opted for consistency by making just one change to the starting XI who ended his side's seven-game winless streak at the weekend, recalling captain Aubameyang following a recent calf issue in place of Lacazette.
Brighton, who did the double over their north London opponents last season, chose to freshen things up following Sunday's 2-2 draw at West Ham.
Graham Potter's six alterations left the hosts with no recognised striker and a starting selection which had contributed a combined total of just five league goals this term.
With both clubs struggling to regularly find the net, it was perhaps unsurprising that there was a lack of killer instinct at either end during a forgettable first half dominated by an abundance of neat passing.
Alireza Jahanbakhsh's 37th-minute drive - which brought a routine save from Bernd Leno - was the game's first attempt on target, while Gunners midfielder Granit Xhaka had earlier been unable to replicate the sublime free-kick he scored against Frank Lampard's side three days ago.
Albion had been the more adventurous side in the opening half but were in serious danger of falling behind early in the second as Arsenal finally threatened.
Aubameyang wasted a golden chance when he diverted Bukayo Saka's left-wing cross straight at Seagulls goalkeeper Robert Sanchez from the edge of the six-yard box, before Martinelli flashed an effort narrowly over.
Gunners keeper Leno - who suffered a season-ending injury here six months ago - denied Davy Propper a goal on his first Premier League appearance of the season, before the visitors were rewarded for their improved second-half showing with what proved to be the winner.
England international Saka burst down the right flank and pulled the ball back, allowing Lacazette to clinically find the bottom right corner and score for the third successive game in all competitions.
Arsenal had not won a league game in Brighton since a 1-0 triumph in April 1981.
The Seagulls threw on Neal Maupay and Leandro Trossard in search of a leveller but never looked like preserving that lengthy unbeaten record as their current troubles continued.