Former Manchester United man Danny Welbeck also found the back of the net at the end of the first half, while substitute Aaron Ramsey scored the third goal just minutes before Giroud's victor.
Vardy's second goal, a towering header from a corner-kick, looked to have won it for the Foxes until the sensational finale that saw the game swing in Arsenal's favour.
But the thing with Chelsea is that they play to the system, are well drilled and the new signings will fit into that system which has shown works so well over the past 12-months.
Arsenal's new signing Frenchman Alexandre Lacazette took 94 seconds to make his mark with a header from Mohamed Elneny's curling cross to equal the record for the fastest opening goal in a Premier League season.
North Korea talk drags stocks lower; gold, yen rise
The Nasdaq Composite dropped 40.64 points, or 0.64 percent, to 6,311.70. "We have not had a 5 percent correction since June 2016". The Nasdaq and the S&P 500 are rebounding after ending Thursday's trading at their lowest closing levels in a month.
It was an incredible escape act from Arsenal, but Giroud claimed his team, who dominated possession and peppered the Leicester goal, never doubted they would hit back. We had a lot of experienced defenders out injured for the game.
After enduring a troubled campaign marred by fan protests against him last season, Wenger desperately needs a strong start this term. "He made a decision to stay and it was one of the great days of recent weeks for me". Not only as a player, he's a fantastic player but as well in the group.
Giroud had been linked with an exit during the summer, and Wenger admitted he considered allowing his most authentic target man to leave but the 30-year-old resisted the idea. At some stage, I opened the door for him because I knew that I had many strikers.
"We wanted to do that today - unfortunately that didn't happen and it's something where we can look back and analyse the game and see where we went wrong and improve on the situation".
Retired Hudson to join Terriers' coaching staff
He ends his playing career having helped Town to promotion via the Championship play-off final against Reading at Wembley. The utility man has already made two appearances for Barnsley this season, adding to his 32 league outings last campaign.
Pochettino forgives Rose for Spurs 'Google' jibe
We are so calm. "Over the last five years Tottenham have always signed players and spent money at the end of the window", he said. My words were not meant to offend and for that I would like to apologise to the chairman, manager, my team mates and the fans.
Sharad Yadav is free to express his opinion, says Bihar CM
Yadav, who is on a tour of Bihar , has said he still believes he is a part of the grand alliance with the RJD and the Congress. This was their first in-person interaction since Nitish reconfigured his government in Bihar to include the BJP last month.
Tillerson says NKorea must halt launches to talk
North Korea had tough talk today for the United States, following the weekend adoption of new sanctions by the United Nations. Before Tillerson's trip, the USA had said he had no plans to interact with North Korean Foreign Minister Ri Yong Ho.
Mourners set to remember woman killed by officer
The memorial finished with a walk in silence around Lake Harriet. "It's rather surreal, but the irony isn't lost on any of us". Ruszczyk's death has caused outrage in the United States and Australia and led to the resignation of the city's police chief.