Nicolas Pepe and Willian both produced their best for some time as Arsenal made the most of Leicester City’s mounting injuries on Sunday.
The result lifted Arsenal two places up to ninth on 37 points from 26 games while Leicester stayed third on 49 points after suffering a second setback in three days following their Europa League elimination.
Leicester, who exited Europe’s second-tier competition with a 2-0 home defeat by Slavia Prague on Thursday, took a sixth-minute lead against Arsenal as Youri Tielemans cut inside the area from the right flank and fired a low shot into the far corner.
The Gunners equalised in the 39th when Luiz headed a Willian cross into the bottom right corner and Lacazette turned the tide in first-half stoppage time as he drilled in a penalty after a VAR check showed Wilfred Ndidi had handled the ball in the area.
Harvey Barnes was carried off five minutes into the second half after appearing to injure his knee stretching for the ball. Jonny Evans soon followed.
Poor defending cost Leicester again in the 52nd minute as they allowed the visitors to break through the middle before Willian slipped the ball to Pepe and the Ivorian forward tucked it into an empty net from two metres.
Arsenal held on comfortably in the closing stages and missed chances to win by a bigger margin as Kieran Tierney volleyed just wide from 20 metres and Pierre-Emerick Aubameyang came close with a fizzing low shot.