Lys Mousset marked his first start for the Blades with the decisive goal in the first half, turning in Jack O’Connell’s knockdown from close range.
Arsenal’s £72m signing Nicolas Pepe had earlier skewed a golden chance wide from six yards.
Granit Xhaka forced Dean Henderson into an excellent save but the Blades closed the game out superbly for a famous win.
The victory was Sheffield United’s biggest result since their return to the Premier League as they moved up to ninth, four points clear of the relegation zone.
Defeat for Arsenal, meanwhile, means they missed the chance to move back into the top four. They are fifth, two points behind Chelsea in fourth.
Sheffield show their steel once again
Sheffield United have certainly shown plenty of grit on their return to the Premier League and have been particularly impressive in not rolling over to sides in the top six.
They battled from two goals down to draw 2-2 at Chelsea in August before pushing Liverpool close at the end of last month, only to be undone by a single goal from a mistake by Henderson.
Chris Wilder had challenged his new-look forward line to give the Blades the cutting edge they have lacked this season and Mousset did just that, making the most of being unmarked inside the box to sweep home.
From then on, it was all about the Sheffield United defence. The hosts, incredibly, have not lost a league game when leading at half-time since 2014 and they managed the remainder of the game superbly, with their back three of O’Connell, Chris Basham and John Egan forming a formidable barrier.
“I have so much respect for Sheffield United’s back three,” BBC Radio 5 live summariser Chris Sutton said. “They have come up through the leagues together, they are well oiled and well drilled.
“It is the best defence in the Premier League this season, along with Liverpool.”
Travel sickness strikes again for Arsenal
The Gunners went into the international break in a good place in the Premier League.
They sat third after beating Bournemouth 1-0 at the Emirates, extending their home record so far this season to four wins and one draw.
But away from home Arsenal remain unconvincing.
Their only win on the road in the Premier League came in their season-opener when they beat Newcastle 1-0 but since then they have scraped draws against Watford and Manchester United and lost to Liverpool and now Sheffield United.
Arsenal have won just four of their last 17 games away from home – a statistic Gunners boss Unai Emery will need to improve quickly if they are to challenge for the top four.
Pepe fails to produce the goods
Ivory Coast winger Pepe arrived at Arsenal in the summer with a big reputation and a big price tag.
The £72m club-record signing had scored 35 goals in 74 appearances for Lille, but he has been underwhelming so far for the Gunners.
The 24-year-old had scored one goal – a penalty – in nine appearances prior to Monday’s game and should have really got his second for Arsenal but managed to miss a chance that looked considerably easier to score.
But despite that error he was arguably the best player in an admittedly under-performing Arsenal team in the first half, and it is easy to forget that it was he who started the move in his own box that led to the chance he missed.
However, Arsenal fans will understandably be expecting him to perform on a more consistent basis to justify his huge price tag.
Man of the match – John Fleck (Sheffield United)
Bramall Lane blues for Arsenal – the stats
- Arsenal have played more Premier League games at Bramall Lane without victory than they have any other ground in the competition (4 – D2 L2).
- Arsenal have lost four of their last seven Premier League away games against newly-promoted sides (W3), as many defeats as in their previous 49 matches (W33 D12 L4).
- Three of the 10 bookings for diving in the Premier League this season have been awarded by Mike Dean (30%), with no other referee issuing more than one this campaign. He gave out two cards for diving on Monday night.
- Since the start of last season, Arsenal have been shown more cards for diving than any other Premier League team (7).
- 13 of Jack O’Connell’s last 14 goal involvements in the league for Sheffield United have come at Bramall Lane, including each of his last eight (3 goals, 5 assists).
- Sheffield United’s Dean Henderson has kept 25 clean sheets in the league since the start of last season; more than any other goalkeeper in England’s top four tiers.
- Sheffield United’s Lys Mousset has scored two goals in six Premier League appearances this season (1 start, 5 sub apps), one more than he registered in 24 games for Bournemouth in 2018-19 (1 start, 23 sub apps).