Inverted pressing? Liverpool the latest confused by United's weird openness 

But this is also about Liverpool and their failure to take chances in key games.

Manchester United's Casemiro (left) and Liverpool's Luis Diaz battle for the ball during the Premier League match at Old Trafford, Manchester. Picture: Martin Rickett/PA Wire. 

Everybody’s done it. The door looks heavy or stiff, so you give it an almighty shove, only to find the expected resistance isn’t there so you tumble through, falling flat on your face. Erik ten Hag’s genius has been to take an everyday pratfall and turn it into a philosophy.

On Sunday Liverpool, astonishingly, fell victim to the trick for the second time in three weeks. The first time put them out of the Cup; this second, although a draw rather than a defeat, cost them leadership of the league.