We suffered a narrow defeat in our opening Mind Series game, as fans returned to Emirates Stadium.
There were more than 20,000 inside the stadium, our largest home crowd since March 7, 2020 when 60,000 packed in to watch us beat West Ham 1-0 in the Premier League.
And although there were moments to cheer - Granit Xhaka's headed equaliser and Ben White making a goal saving block on his debut - we ended up on the wrong side of the scoreline.
Roared on by the crowd - many of whom had waited a long, long time to be back - we made a flying start. Pierre-Emerick Aubameyang got in behind the defence a couple of times. First he sent a cross just ahead of Emile Smith Rowe in the box, then set Kieran Tierney away with a neat back flick.
After a lively opening ten minutes, the game began to settle down, and there were no real chances for either side before Chelsea took the lead, out of nothing. Timo Werner set up his compatriot Kai Havertz on the break, and the midfielder slammed his shot past Bernd Leno in the Arsenal goal.
We went searching the equaliser, and nearly had it moments later - Smith Rowe was unlucky to see his left footed shot from the edge of the area thump off the bottom of the post.
Thomas Partey had impressed in the opening half hour, but he was forced off the pitch with an injury, to be replaced by Granit Xhaka - making his first appearance of pre-season.
Chelsea hit the post themselves, through Hakim Ziyech, and committed a succession of fouls as the half ended in scrappy fashion.
Ben White came on at half-time for his debut, replacing Rob Holding, and was soon in the action as Chelsea began the second half well. His first meaningful touch was a goalline block to deny Ziyech after the Moroccan had rounded Leno.
At the other end Nicolas Pepe saw a shot deflected just wide while Alexandre Lacazette had a low free-kick well saved by Edouard Mendy.
We were knocking on the door and soon had the equaliser - From a corner, Xhaka rose highest in the penalty box and planted his header into the net. The crowd erupted, but the joy was short lived.
A few minutes later Tammy Abraham pounced on a loose Hector Bellerin pass on the edge of our area, and tucked the ball in.
Arteta made a host of changes, introducing Nuno Tavares and Sambi Lokonga for their first Emirates outings.
Another sub, Joe Willock thought he had equalised when his thunderous shot bounced down back off the bar, but the officials agreed it didn't cross the line. Replays suggested otherwise.
White made another goalline stop late on, with Aubameyang coming close, but the afternoon ended in frustration.
None of the three summer signings were included in the starting XI, but Mikel Arteta named a strong side for our fifth run out in pre-season. Captain Pierre-Emerick Aubameyang was included in attack alongside Nicolas Pepe and Alexandre Lacazette, with Emile Smith Rowe in the No. 10 role.
Thomas Partey partnered Mohamed Elneny in midfield in front of a back four of Kieran Tierney, Pablo Mari, Rob Holding and Calum Chambers. Bernd Leno was in goal.
The last game of the Mind Series - and our final pre-season friendly – takes place next Sunday at 3pm (UK time) at the Tottenham Hotspur Stadium, against our north London rivals. Chelsea and Spurs meet before that in the Series, this Wednesday evening.
Then the real action kicks off on Friday, August 12 at 8pm (UK) when we visit promoted side Brentford on the opening day of the 2021/22 Premier League season.
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