Sheffield United halted Arsenal's eight-match unbeaten run with a telling 1-0 victory over Unai Emery's men.
A timely opening in the 30th minute from Lys Mousset - in his first start for the Blades - eventually resulted in the most important touch of the game as the visitors struggled to carve open a sturdy, robust, determined Sheffield backline.
While the Gunners headed into this fixture on the back of five wins in six, Chris Wilder's men had to make a point to their pious supporters, who had stood witness to three consecutive home losses prior to this match-up.
"For the club to host a game like this, the magnitude of it - to play well and get a win is massive. We came under pressure in the second half but we limited them to a few chances and we backed up a good performance with a good result," said Wilder, after his side held on to keep their lead.
The win now means Arsenal have slipped to fifth place, two behind Leicester City and fierce rivals Chelsea, whereas Sheffield United's gritty football has seen them jump to ninth place, level on points with Bournemouth, Burnley, and Tottenham.
On that note, we look at five players who experienced contrasting fortunes at Bramall Lane.
#5 Hit: Dean Henderson
Dean Henderson put in another splendid display following that spill against Liverpool three weeks ago. The Englishman was decisive with his positioning, ordering, and timing throughout the evening.
Against a stacked Arsenal attack, he ought to be.
In total, he made three commendable saves on the evening. He kept out a Pepe free-kick which was more or less comfortable, but a timely dive at full stretch to thwart Granit Xhaka's thunderous effort from distance was spectacular.
Owing to his alertness, Henderson's performance looked far easier than it actually was. He has responded well since the Liverpool blunder and now stands out with an incredible 26 save-tally in the Premier League this season. Well-deserved clean sheet.
#4 Flop: Sokratis Papastathopoulos
Since the start of the season, injuries coupled with horror shows at the back have limited Arsenal's all-round game to mere spark in attack. Their backline has to improve by a significant margin if they have to bid for a place in the Champions League spots.
Arsenal's center-halves are just not working as a duo, and are fairly struggling against the pace and tactics of various counter-attacking oppositions. The same followed suit this time around, as David Luiz and Sokratis were caught off guard a handful of times.
They could have done much better in winning the first ball during the corner as well, which in turn was a routine off the training ground.
Sokratis couldn't keep at pace with Mousset, who threatened down the channels with willing runs and darts. He wasn't sharp enough or clinical with his tackling either. It's time Rob Holding receives the license to express himself at the heart of the Arsenal shield.
#3 Hit: Lys Mousset
On the first start for his new club, Lys Mousset repaid his manager by rounding off a well-constructed move.
A simple yet effective stroke of play saw Jack O'Connell head the ball back across to an unmarked Mousset, who poked home from close range, leaving Arsenal staring down the barrel on their travels for the umpteenth time in recent weeks.
He scored a fine goal against Everton, and he repeated the same against Arsenal. The former Bournemouth forward has an uncanny ability to keep pushing for the extra yard, run his socks off and give it all.
He caused a whole lot of issues to Sokratis and Luiz with his runs off crosses, diagonals, and most significantly, straight down the channel in between the Gunners' center backs.
The 23-year-old doesn't promise 20 goals a season, but his movement in and around the box is quite an asset to have as a number nine.
#2 Flop: Granit Xhaka
Not for the first time, Granit Xhaka blew hot and cold in the middle of the park during Arsenal's 1-0 defeat.
He's got a stunning eye for goal, yes, as portrayed in the fierce long-distance strike. But otherwise, Xhaka is extremely careless and reckless while defending. On the ball, he wasn't as productive or incisive, as a packed Sheffield defense disallowed any crafty passes.
On the other end, Xhaka was involved in a couple of clumsy challenges, besides also paying the price for losing possession at key junctures.
What's horrendously unacceptable is his lack of awareness in the middle. Repeatedly, the likes of John Fleck and Oliver Norwood were allowed to run through his lines, get past in between and dictate the pace of play.
As far as the midfield battle is concerned too, the Swiss failed to keep pace or inspire his side to recoveries.
#1 Hit: Jack O'Connell
Jack O'Connell's story is nothing short of inspirational. Five years back, he captained Rochdale to promotion from League Two, before which hardly anyone knew of him. The 25-year-old has grown leaps and bounds since, and is here now, keeping the likes of Nicolas Pepe at bay.
The central defender, on the left side of the back three, showed immense keenness to get forward, whip crosses in and attack, as per the requirements of Chris Wilder's unique system. Alongside Chris Basham, the duo remained the focal point for Sheffield's top chances for most of the game.
On the defensive front, he was safe as a house. Grasping the opponent's next move, picking up runs and standing tall while defending were glimpses of his confidence and conviction.
Further, O'Connell and Sheffield United's glorious performances do not correspond to an individual but collective collaborations at the back. The same unfolded at Bramall Lane, as all the three defenders were on top of their game.
Oh yes, O'Connell's fine flicked header led to the winner as well.