Leicester took the lead in the first half when Ben Chilwell's attempted cross was deflected into his own net by Hector Bellerin.
But Bellerin redeemed himself just before half time when his cross was deftly finished by Mesut Ozil.
Bellerin then got his second assist of the night when his ball across the box was finished by Pierre-Emerick Aubameyang.
And Aubameyang got his second and Arsenal's third when he tapped in an Ozil flick.
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Here's five things Express Sport learned:
Captain Ozil
Eyebrows were raised when the Arsenal team was announced and the German was named the captain.
But after a quiet start, the 30-year-old produced a virtuoso display.
His goal before half-time oozed class. He then delivered a defence-splitting pass which led to Arsenal's second goal.
He then got an assist after another flowing move led to a goal for Aubameyang.
Ozil was then given a deserved standing ovation by the Emirates crowd when he was taken off.
Super-sub Aubameyang
Aubameyang was surprisingly named on the bench by Unai Emery.
But the striker showed his manager what he is capable of with two goals as a sub.
Emery has an abundance of attacking options at his disposal.
Shaky Arsenal defence
But Arsenal's win could and probably should have been a lot harder to achieve.
Leicester bossed the opening 30 minutes and deservedly took the lead through Chilwell.
And their threat exposed Arsenal's defence which will be a concern with tougher tests to come in the next few weeks.
Anonymous Vardy
Jamie Vardy loves scoring against Arsenal but today was not his day.
The former England striker offered little in attack compared to the lively James Maddison.
And Vardy quietly ran off the pitch with an injury to leave his side down to ten-men late on.
Improving Iwobi
One of the biggest plusses for Arsenal this season has been the improved form of the Nigeria international.
Confident on the ball, an improved final ball, energy and work-rate.
The 22-year-old is getting better and better.