Manchester United looked to be in the driver's seat against Aston Villa based on their first-half performance. Thanks to a freak Bruno Fernandes free-kick, they had created several chances and were ahead.
In the second half, the cracks began to show, but when Fernandes added to his tally with a fiercely struck shot, the team must have felt comfortable that the game was won and it would be another three points under Ralf Rangnick.
But then the wheels came off.
Rangnick had learned a lot against Aston Villa from their cup game and chose to start with the 4-3-3 formation to good effect to exploit the fact that their fullbacks push high and get the best out of his lone striker Edinson Cavani, who led the team's press.
But Steven Gerrard, Aston Villa's manager, had also learnt lessons from that game and what he realised is that United's new-brand high energy football can not be sustained for 90 minutes. It was even more apparent when they were forced to play Nemanja Matic in the number six spot due to a lack of options.
So Villa soaked up the pressure as much as possible and then late in the game brought on their new gamechanger Philippe Coutinho, and it all fell into place.
First, Jacob Ramsey scored, and then Coutinho equalised, and it was fortunate for United that the Brazilian did not go on to grab the winner. Still, the team had successfully exposed a weakness that other teams can now exploit.
And United need to be wary that Brentford does not exploit the team in the same way. Ralf Rangnick has stated that he will deploy a similar formation for the Premier League fixture, with a six at the base. Luckily, United will have Scott McTominay back from suspension, so they will not have to rely on Matic wholly.
Now Brentford in a different formation embodies the same ideals as Aston Villa. Their wingbacks offer options out wide to play balls across the backline, and their strikers of Ivan Toney, Bryan Mbuemo, or Yoane Wissa play in tandem to break down and disorganise defences to create chances.
So if the London side can keep United modest early on and stay in sight, they may be able to grab a result or even win against Rangnick's men.
United will also have to be wary of Brentford. The newly-promoted side collected a win against Arsenal and a draw against Liverpool while putting up fights against Chelsea and Manchester City only to lose 1-0.
United have improved under Rangnick, and the first half against Aston Villa was some of the best football the team have played under Rangnick, but as the old saying goes, it's a results business, not a performance one.
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