But Ozil returned to training this week and is expected to feature in the opening Premier League game of the season tonight (7.45pm United Kingdom time) when Arsenal host Leicester.
Danny Welbeck then made it 2-2 on the stroke of half time, but Vardy had given Leicester the lead once again in the 56th minute.
Leicester showed some of the form that won them the title in 2016 and helped stave off relegation last term but in the end they were undone by canny France worldwide Giroud who has been linked with a move away from Arsenal all summer.
Instead, Wenger avoided a third successive season-opening loss at the start of his new two-year contract.
However he has been named to start of the bench in the first match of the season.
Two minutes later, the comeback was complete, with super-sub Giroud sending the home fans wild via magnificent header from a Xhaka corner, despite being held by Wes Morgan.
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With the injured Alexis Sanchez looking on from the stands, Arsenal took the lead inside two minutes as Mohamed Elneny's cross to the centre of the box found Lacazette, who flicked a header inside the post.
France striker Giroud netted a dramatic victor less than two minutes later when the 30-year-old rose above the Leicester defence to secure three points. "You want the Premier League to be the best league in the world and I think it has to produce this kind of games to produce interest and quality", he said.
Key Player: Alexandre Lacazette - There is pressure on Arsenal's marquee signing to score the goals to push them towards the title.
"It's an important game for us because afterwards we go away to Stoke and to Liverpool".
Alex Oxlade-Chamberlain seemed most determined to equalise for Arsenal. "Overall we have many games and hopefully I can give a good number of games to all of my strikers".