This was a story of two contrasting individual performances: one, a brilliant solo display from Callum Hudson-Odoi; the other, a bad off-day for Alvaro Morata.
There's nothing like an early goal to kill optimism in pre-season, and the strike which gave Chelsea a fifth minute lead was too easy. Cesc Fabregas' corner was right onto the head of Antonio Rudiger, but he had far too much space to plant his header into the bottom corner of Petr Cech's net.
Arsenal were looking very...Arsenal. That is to say, too clever going forwards and not nearly clever enough at the back. Despite all the international stars in Chelsea's lineup, it was the youngster Hudson-Odoi who was really turning heads with his performance.
Time and time again his terrific pace and composure had Hector Bellerin on toast, and eventually the Spaniard could stand it no longer, bringing down the twinkle-toed 17-year-old for a clear penalty.
Hudson-Odoi the 17 year old has Bellerin breakdancing. I love this game.— َ (@HazardEdition) August 1, 2018
Jorginho & Hudson-Odoi almost just made a baby on the damn pitch.— Alex Goldberg (@AlexGoldberg_) August 1, 2018
My heart can’t take this.
Morata stepped up to take the penalty, to put last season behind him, to show Maurizio Sarri why he deserves to start. This would be the start of his road to redempt...
But Cech saved it. And Petr Cech doesn't save penalties.
Petr Cech hasn’t saved a single penalty in his entire Arsenal career...— Nice’Guylo Kenté (@NiceGuyKenny) August 1, 2018
Alvaro Morata: hold my hairdryer....
Petr Cech saved a penalty, the end is near— Fady Ashraf (@FadyAshraf) August 1, 2018
PETR CECH HAS SAVED A PENALTY, I REPEAT PETR CECH HAS SAVED A PENALTY. IT’S NOT A JOKE— Lacazettes (@Lacazettes) August 1, 2018
Arsenal certainly improved in the last 20 minutes of the half with some nice intricate play in the final third, but Willy Caballero was barely tested as the Gunners lacked a cutting edge. Their half was epitomised when a goalbound Henrikh Mkhitaryan shot deflected away off one of his own players.
At the other end, the rest of the half could be summarised by the same sentence template: "Hudson-Odoi [good thing], but then Morata [bad thing]".
As in, Hudson-Odoi teased the Arsenal defence with a pacy run, but then Morata hit it straight at Cech. Or, Hudson-Odoi played a dangerous pass across the Arsenal area, but then Morata completely mishit it.
Morata struggling. Water is wet.— CFC (@CFCWriter) August 1, 2018
Hudson-Odoi is singlehandedly trying to recreate Morata, but Morata be like, “nah, I prefer to struggle.”— Alex Goldberg (@AlexGoldberg_) August 1, 2018
Chelsea went in ahead, and deservedly so. However, it was Arsenal who emerged for the second half with renewed purpose, but again they were struggling to make Caballero work.
By contrast, one of Chelsea's first forays forward forced Cech to be alert. Hudson-Odoi whipped in a great cross from the right, but then Morata...you know how this sentence ends.
The first glut of substitutions came just after the hour mark, putting an end to one of the most compelling narratives of the night as Sarri brought off the frustrated Morata.
Arsenal should have equalised with 15 minutes left as Alexandre Lacazette did brilliantly to work his own space in the box but then dragged his effort wide of Caballero's upright. Alex Iwobi was then denied by an instinct save from substitute goalkeeper Marcin Bulka.
Hudson-Odoi's second half had been quieter than the first, but he still got a standing ovation from the crowd when he was taken off in the last 10 minutes. He has certainly given Sarri something to think about before Sunday's game at Wembley.
Bulka made another fine save in injury time, but from the resulting corner Arsenal got an equaliser they probably merited. Mesut Ozil's disguised pass found Reiss Nelson, who drilled in a cross from which Lacazette couldn't miss, taking the game to penalties.
Lacazette did not let that earlier miss affect him and he got his reward for a good performance since he came on.— MR DT © (@MrDtAFC) August 1, 2018
Ozil what a disguised pass— PAUL BLOICE (@PaulBloice) August 1, 2018
In the shoot-out, both teams were perfect for the first ten penalties, with neither goalkeeper even coming close to making a save.
In the sixth round though, Ruben Loftus-Cheek was denied by Cech and Iwobi stepped up to give Arsenal the spoils.