#3 United's defensive record
If Manchester United were splendid in defence last season, then this season they have embarked to become even more superior. Conceding just 9 goals in 15 matches, Manchester United's defence has been absolutely solid. In the Premier League, Manchester United hold the record for conceding the least amount of goals this season.
Marcos Rojo, Chris Smalling, Antonio Valencia and Ashley Young look to be in top form. Victor Lindelof was the only defender that was looking a bit shaky at the start of the season, but in recent matches, he too has regained back his form which he showed while playing for Benfica.
Even if the defence gets beaten, they have arguably The world's best goalkeeper behind them, who saves United's bacon most of the time. Ask Arsenal about it!