The Gunners were on the brink of losing two points as the added-time minutes ticked by, but two very late goals ensured a healthy scoreline for the hosts.
Gabriel Martinelli opened the scoring for Arsenal in the 20th minute of the game when he finished off from Jurrien Timber’s low delivery from the right.
Leandro Trossard then doubled their lead on the stroke of half-time, twisting his body and redirecting Martinelli’s pass into the net.
However, Leicester rallied round as James Justin scored a brace, including a superb volley off the post, to stun the Emirates Stadium.
Then, in the 94th minute, a corner was swung in which Trossard kept alive, and Wilfred Ndidi put the ball through his own net by mistake.
Arsenal got a fourth three minutes later as Gabriel Jesus broke with pace before the ball fell to Kai Havertz and trickled over the line, with VAR deeming it a goal.
All in all, it was a solid performance from Arsenal, who simply never gave up and who once again showed how good they are from set pieces.
Likewise, Trossard once again showed how reliable he is despite not always starting, as he got on the scoresheet and then helped get the all-important third goal.
Martin Keown loved what he saw from the £26million man, saying he is “worth every penny” and lauding the fact Arsenal got yet another goal from a corner.
“What a buy Leandro Trossard was! Worth every penny,” Keown said on BBC Sport. “A perfect day if it finishes like this.
“Arsenal score from a set-piece – who’d believe it? Arsenal just kept believing. It is a lucky goal and ‘lucky Arsenal’ is a nice tag to have.”