Arsenal ignore injury woes to retain top spot with win over Brighton
Mikel Arteta's side were already without a host of defenders before Riccardo Calafiori was injured just before kick-off at the Emirates Stadium.
The Gunners made light of those absences as Martin Odegaard put them ahead in the first half before Georginio Rutter's second-half own goal increased the lead.
Diego Gomez got one back for Brighton but Arsenal held on for a third successive league victory.
Arsenal sit two points clear of second-placed Manchester City, who had briefly moved above them after beating Nottingham Forest 2-1 earlier on Saturday.
The north Londoners host title rivals Aston Villa in their next match on December 30.
Arteta was forced to field a team without a recognised right-back due to the injury bug and the situation got even bleaker when Italy's Calafiori suffered a knock in the pre-match warm-up.
Cristhian Mosquera, Ben White and Jurrien Timber were also sidelined, so Myles Lewis-Skelly came in at left-back and England midfielder Declan Rice started at right-back.
Despite their issues in defence, Arsenal tore into Brighton and should have taken an early lead when Viktor Gyokeres seized on Lewis Dunk's mistake, only to shoot straight at Bart Verbruggen.
Bukayo Saka was next to threaten after slaloming past Maxim De Cuyper, but Verbruggen saved at his near post.
The Gunners' barrage was rewarded in the 14th minute as Verbruggen's poor goal-kick was pounced on by Saka and he teed up Odegaard for a fine low finish from the edge of the area.
It was the Arsenal captain's first goal this season, ending a personal goal drought stretching back to May.
Rice nearly made it two but Dunk cleared his shot off the line before Verbruggen made a brilliant save to repel a clever flicked effort from Gyokeres.
Arsenal had won all 11 league games in which they scored the opening goal this season and that impressive record was destined to remain intact.
They moved further ahead in the 52nd minute when Rutter headed Rice's corner into his own net, extending Arsenal's remarkable record of scoring from set-pieces this term and making it four own goals in their last six goals.
Out-classed Brighton failed to manage a single shot in the first half, so it was a major surprise when they got one back in the 64th minute.
Yasin Ayari's shot cannoned back off the post and Gomez reacted quickest to slot home from close range.
Arteta responded by sending on Brazil centre-back Gabriel Magalhaes for his return from a thigh injury suffered in early November.
But nerves were starting to jangle among Arsenal fans and Yankuba Minteh almost sent them into a full blown panic with a long-range blast that was destined for the top corner until Raya made a brilliant tip over.