Olivier Giroud came off the bench to head home a late winner and seal three points for Arsenal in a topsy-turvy Premier League opener against Leicester.
The Gunners had won just one of their last seven opening-day fixtures and looked destined to start another campaign slowly as the 2015-16 champions took the lead twice only to lose 4-3.
The night started perfectly for Arsenal as new signing Alexandre Lacazette marked his league debut with a goal after just 94 seconds, only for Shinji Okazaki to cancel it out three minutes later.
Jamie Vardy then capitalised on awful defending to twice put the Foxes ahead either side of Danny Welbeck’s equaliser before Arsene Wenger sent on the cavalry.
Substitute Aaron Ramsey rifled home to level before Giroud – introduced alongside the Wales international – headed in an 85th-minute winner to settle a breathless encounter in Arsenal’s favour.
Lacazette converted his first chance in the Premier League, heading home Mohamed Elneny’s inch-perfect cross to send the home fans into raptures.
But Arsenal’s defence, with essentially two full-backs playing in their back three, were soon caught out having been given a warning when want-away Leicester winger Riyad Mahrez volleyed wide.
Petr Cech was largely at fault, coming off his line but getting nowhere near Marc Albrighton’s deep cross as Foxes debutant Harry Maguire headed back across goal for Okazaki to nod in.
Arsenal reacted well and started to box Leicester in, Welbeck seeing a shot blocked before he dallied on a later effort.
Sead Kolasinac marked his debut with a goal in the Community Shield and forced Kasper Schmeichel into a smart save here with a driven shot from just inside the box, but the Gunners again fell behind to Vardy’s strike.
Elneny played a pass to Granit Xhaka who, with very little space, gave the ball away to Albrighton and the former Aston Villa man crossed for Vardy to tuck away his chance from close range.
Okazaki nearly made Arsenal’s first half even more galling but he could only head narrowly wide with the home defence all over the place.
Arsenal wanted a penalty for handball against Wilfred Ndidi with referee Mike Dean unmoved, but the equaliser came on the stroke of half-time after Kolasinac unselfishly squared to Welbeck with the goal gaping.
Mahrez saw an effort tipped over by Cech as Leicester looked to regain their advantage – something they did from the resulting corner as Vardy, completely unmarked, headed home the Algerian’s set-piece.
Schmeichel was alert to prevent Hector Bellerin finishing off a slick Arsenal attack before Ramsey headed inches wide with his first touch.
With time running out, Ramsey made sure he did not make the same mistake as he fired past Schmeichel from Xhaka’s pass with eight minutes remaining. There was, however, a strong suspicion of handball by Ozil ahead of the corner that indirectly led to the goal.
Schmeichel’s brilliant diving stop denied Lacazette a fourth but, from the corner that followed, Giroud headed home off the underside of the crossbar to seal a remarkable three points.
Arsenal goalkeeper Petr Cech on dramatically being on the winning side: “We started really well, we got the first goal and I thought it was the moment where we could control the game but then we made mistakes and they punished us.
“They had two half-chances and put them in and we had to chase again and I thought going in at 2-2 at half-time it was our advantage, but then the corner gave them the advantage again and we had to chase again.
“They were difficult moments when we were 2-3 down but we managed to get out of that and found two goals, which was great to see.
“We made some technical mistakes, for example the second goal, but that can happen, that’s part of football. They put a great ball in and Jamie Vardy does what he does best.
“Overall we showed great character. First game of the season we played a classic, so for everybody at home it will have been amazing to watch.”
Arsenal striker Olivier Giroud on a dramatic start to the season: “I knew I had the chance of coming on in the game. We tried to push, we kept believing in our game, carried on, pushing hard and we’ve been courageous to the end and thank goodness we won this game.
“That’s a nice start but obviously I prefer to be on the pitch.
“But as much as I can I will try to help the team to reach our target and tonight we needed this win as everybody knows the importance of the first game for confidence and we keep going.
“I’m very pleased for the team and hope we can carry on.”
Arsenal boss Arsene Wenger on Giroud: “I love the man and the player because he’s a fantastic guy as well, committed, he loves the club.
“He doesn’t want to leave and I’m happy that he wants to stay, but at some stage I opened the door for him because I knew I had many strikers. But he’s really loved here, we love him, and in the end he’s decided to stay.”
Wenger on his other goal-scoring substitute Aaron Ramsey: “I didn’t want to take a gamble (with Ramsey) because a few times when I took it he got injured at the start of the season – last season the first game against Liverpool.
“So overall I’m pleased that he could come on today and not be injured.”
Wenger on the final result: “You win 4-3, you’re more happy than concerned, you know,” he added.
“I feel as well that the goals we conceded, we can work together to get rid of that because one was a ball we lost in the build-up and we conceded two goals on corners.
“We were quite good last year on corners and I believe with a bit of work, we can get that out of the system.”
Leicester boss Craig Shakespeare on the outcome: “You come away from home, score three goals and are nearly there and then concede two…bitterly disappointed.
“I’m always looking for the positives, we came to the Emirates and the players executed the game plan. We were a threat and played football and contributed to a thoroughly entertaining game.”
Shakespeare on whether Riyad Mahrez will stay at Leicester: “Who knows?
“I think we have all seen the funny business of the transfer window and we never know what is round the corner. Riyad has been very focused.
“He came out and made a statement which we are all aware of but while he trains and plays and is professional the way he is, he will be considered for selection.”