Arsenal is not just pursuing a first league title since 2004 but also a return to the top four " and Champions League qualification " after finishing fifth in May.
Arsene Wenger has confirmed that he gave Olivier Giroud the chance to leave Arsenal this summer, but the powerful striker chose to stay put despite rumoured interest from a number of suitors including Everton.
Mahrez almost equalized less than two minutes later in sensational fashion, with his volleyed attempt off a set piece going tantalizingly wide of Petr Cech's goal.
But Gunners responded well with former Manchester United player Danny Welbeck tapping the ball in open net just before half-time.
Leicester took the lead right back just before the hour mark, scoring off another set piece.
Vardy notched his second of the evening with a fine glancing header from a Riyad Mahrez corner on 56 minutes to give Craig Shakespeares side a slender advantage.
2 goals from two substitutes late, and all was rosy in Wenger's world.
"If you cut the team in half, attacking wise they look great on paper and they showed that with some intricate passing - it was outstanding at times".
On the ensuing corner, the go-ahead strike came, and it came off the head of Giroud.
Arsenal have won their last three home matches against the Foxes.
Arsenal continued to have issues against the high press throughout the match, especially Rob Holding and the back line.
But the forward will no doubt be hoping to win more fans round if he continues to pop up with crucial goals this season.
"It's impossible to keep them happy when strikers don't play".
Having seen Zlatan Ibrahimovic make a seemingly seamless transition from Ligue 1 to the more physical Premier League last season, the experienced coach expressed optimism that Lacazette would follow suit.