But Unai Emery's side continued to cut Chelsea open and they hauled themselves level in dramatic fashion, scoring two goals in four minutes as Mkhitaryan drove in fiercely from the edge of the box before Alex Iwobi converted the Armenian's cut-back before the break.
It was only the second match of the 2018-19 campaign for both teams, and it showed.
On the touch-line, Sarri, wearing a baggy blue T-shirt and track-suit pants, waved his arms in frustration as he implored his players to close Arsenal down in their own half as the Gunners showed signs of fighting their way into the game.
Wallabies setback: 'Tongan Thor' Taniela Tupou ruled out of Bledisloe opener
He has been replaced on the Wallabies bench by uncapped Melbourne Rebels tighthead prop Jermaine Ainsley. Camera IconJack Maddocks will make his Wallabies debut from the bench.
Chelsea boss Maurizio Sarri insists his side can not be considered as Premier League title contenders just yet, despite Saturday's thrilling win over Arsenal. The defensive phase of all the team, all the players. This, however, probably wasn't what he had in mind. Maybe there's one moment where he misses three good chances, but another where they'll score three chances that are less clear.
And Kovacic is set to get that at Chelsea with Sarri planning to partner him with N'Golo Kante and Jorginho in a midfield three.
The Blues lost 2-0 to Manchester City in the Community Shield at Wembley to lose their first competitive clash under the Italian coach.
Unlike last week's loss to Man City, the Gunners can take plenty of positives from this match. Needing a morale-boosting result after last week's defeat at home, they were up against one of their chief rivals, who also happen to be among the richest clubs on Earth.
It was a true rollercoaster game, with the Blues going two goals up early on before conceding another two in an action packed first half. Both Shkodran Mustafi and Sokratis Papastathopoulos were easily beaten for pace when Chelsea played long balls over the top. The finishing will sharpen as the season goes on. "We need to give the players calm and continue working".