'Wenger Out' trends on Twitter after just 30 mins

It took just a handful of minutes for Arsenal fans' enthusiasm to wane away at the start of this new season - and a few more for a familiar chant to pick up speed.

Alexandre Lacazette's goal in the second minute had the Gunners dreaming of the Premier League title, infinite riches and world domination as they hosted Leicester City in the season's opening clash on Friday night (Saturday morning AEST).

But those dreams quickly turned sour when Shinji Okazaki levelled, and by the time Jamie Vardy had given Leicester the lead supporters had seen just about enough.

Just 30 minutes is how long it took for 'Wenger Out' to start trending again on Twitter, even if Danny Welbeck calmed some nerves by sending Arsenal into the break level at 2-2.

Arsenal twice came from behind to eventually beat Leicester City 4-3, with Olivier Giroud heading home a late winner.

Gunners manager Arsene Wenger, who will be seeking a first league title since 2004 after being handed another two years in charge, was a relieved man after the match.

"Going forward and character wise we have been great," Wenger said.

"We had some avoidable goals which we conceded and overall we have to work on that," he said referring to poor marking in the by his team's defence.

Arsenal's quickfire lead lasted barely three minutes before Marc Albrighton's cross from the left was headed back into the middle by Leicester's new signing Harry Maguire and Okazaki nodded the ball past flailing Arsenal keeper Petr Cech.

Vardy put the visitors 2-1 ahead just before the half hour, darting into the box to rifle another fine Albrighton cross past Cech after the winger had pounced on a poor square ball from Arsenal midfielder Mezut Ozil.

But Welbeck had the last word of the first half for the home side when he equalised from close range in added time after new signing Sead Kolasinac's tap forward in a goalmouth melee.

The impressive Vardy scored his second in the 53rd minute to put Leicester in front once more, curling Riyad Mahrez's corner into the bottom far corner amid poor Arsenal marking.

But the home side's pressure in the final half hour turned the game back their way and Ramsey equalised with a shot from close range with seven minutes remaining.

Giroud then sent the previously despondent Arsenal fans wild when he headed the 85th minute winner from a corner, Leicester keeper Kasper Schmeichel only managing to turn the ball onto the underside of the bar before it bounced over the line.