Once again, Unai Emery's Arsenal struggled away from home.
Lys Mousset scored the sole goal in a match the north London side never looked like winning.
Arsenal now fall to fifth in the Premier League, sitting two points behind third and fourth placed Leicester and Chelsea who are in 17 points.
Here's how he rated following Arsenal's trip to Sheffield United.
Team selection
Although Emery's team selection is becoming more consistent, it isn't having the desired effect.
As has been the case throughout this season, Arsenal failed to impose their own identity on a lesser team. Instead, Sheffield United dictated terms with an adventurous, courageous identity on the Gunners from the jump.
In the opening exchanges, they targeted Arsenal's right where Nicolas Pepe was paired with Calum Chambers. This gave them a real foothold in the game and they returned to this area of the pitch across the 90 minutes.
Although Hector Bellerin is being eased back into action, this could have been the perfect time to bring him back into the fold.
As for the midfield, they offered little. As a trio, they just didn't work. Granit Xhaka was too slow in his build up and couldn't get Arsenal moving through the lines.
Maybe a certain German World Cup winner could help Emery break down stubborn defences. 2/5
Tactics
The biggest fault from Unai Emery against Sheffiield United was how he tried to get his side to build attacks.
Sheffield United were always advancing forward when out of possession.
As a result, whoever dropped to receive the ball was isolated as passing lanes to the more advanced midfielders became clogged.
Therefore, Granit Xhaka, Matteo Guendouzi and David Luiz, who also took on this responsibility, were forced to pump the ball long where Arsenal's forwards couldn't keep hold of the ball.
When Arsenal finally got into the final third, they were too static. Waiting for gaps in the United defence that were never going to open as they whipped around the box side to side. 2/5
Substitutions
The Spaniard returned to the half-time substitutions Arsenal fans became familiar with last season and although was a bit of an impact, there wasn't enough of one.
Dani Ceballos replaced Joe Willock for the second-half and Arsenal were able to get higher up the pitch. Despite this, Ceballos didn't add much in the final third and was quite pedestrian.
When Alexandre Lacazette was introduced, Pierre-Emerick Aubameyang was shoved to the left wing.
Although the substitution was positive, having the pair closer together would have worked better. Lacazette brought a presence to Arsenal's frontline but was often islolated.
Bringing Pepe off when he did seemed weird as the Ivorian was getting into the game but without much to show from his performance, bringing on Martinelli couldn't hurt. 3/5
In-game changes
Although Emery appeared to change things with his substitutions, not much actually did.
Chris Wilder's side were still confident and able to cut through Arsenal with ease. Although the Gunners saw more of the ball in the second-half, their attacking efforts were futile.
They lacked imagination and couldn't seem to cope with a defence that wouldn't lose their shape.
Overall, it was a very disappointing night for Emery and Arsenal, especially coming off the back of an international break. Now onto Vitoria in the Europa League. 1/5
