Brighton, who have yet to win at home this season, held their own in the first half with the best chance falling to forward Alexis Mac Allister as he cut inside before curling a shot just over the crossbar in the 36th minute.
The second half opened with a penalty appeal for Brighton whose defender Lewis Dunk tripped over Mohamed Elneny as he tried to reach a corner, but the video assistant referee deemed the contact to be accidental.
Arsenal enjoyed plenty of possession but struggled to create chances, with Pierre-Emerick Aubameyang going closest five minutes after the break as Brighton keeper Robert Sanchez managed to deflect the ball behind for a corner.
Laca leading the way 🎺#BHAARS https://t.co/dJHO7KwseN
— Arsenal (@Arsenal) 1609277128000
Lacazette replaced Gabriel Martinelli in the 66th minute and wasted no time putting his side ahead, taking a touch to control Bukayo Saka’s pass in the penalty area before curling the ball into the bottom corner.
Brighton never looked like equalising and the defeat leaves them in 17th place on 13 points from 16 games, two points above the relegation zone.
Keep the ball rolling! ✊#BHAARS 🔵 0-1 ⚪️ (FT)
— Arsenal (@Arsenal) 1609271488000
After a rocky run of seven games without a win came to an end against Chelsea on Boxing Day, Arsenal’s first back-to-back victories since the opening two games of the season in September moves them up to 13th on 20 points.
Weeks like these 😍✊ Onto #WBAARS! https://t.co/xOLQ9ymqDa
— Arsenal (@Arsenal) 1609284660000
“I’m proud for the boys and happy for the result. Lacazette is in a good moment, he’s full of confidence,” said Arsenal manager Mikel Arteta.
“We know we’ve been struggling with results, (and) the fact we won against Chelsea was a big boost. To come here and get another win was massively important,” he added.