An own goal from Hector Bellerin saw Leicester take a 31st-minute lead in London, but Arsenal then scored three times without reply to make it 10 straight wins in all competitions.
The Gunners have now been victorious in their last seven Premier League matches, and have moved above Tottenham Hotspur into fourth position in the table, just two points off the summit.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
ARSENAL (4-2-3-1): Leno; Bellerin, Mustafi, Holding, Lichtsteiner; Xhaka, Torreira; Mkhitaryan, Ozil, Iwobi; Lacazette
LEICESTER CITY (4-2-3-1): Schmeichel; Amartey, Maguire, Evans, Chilwell; Mendy, Ndidi; Ricardo, Iheanacho, Maddison; Vardy