Casemiro substituted after two goal-leading errors against Liverpool

At Old Trafford, Luis Diaz gave Liverpool a 2-0 advantage in just seven minutes, both goals coming from errors made by Casemiro. Ryan Gravenberch stopped Casemiro's attempted pass in the 37th minute, allowing Diaz to finish off his cross from Mohamed Salah. 

Soon after, Salah worked the ball to Diaz, who scored his second goal of the game after Casemiro effortlessly shrugged off the ball. At halftime, Toby Collyer entered the game in place of the former Real Madrid midfielder, receiving his Premier League debut.

Diaz was clinical, but his accomplishments were only made possible by Casemiro's mistakes. Giving goals to your rivals isn't going to work for United, who want to contend for the English Premier League crown once more. Given the result, the midfielder's teammates have every reason to be angry with him, given he also proved a liability occasionally during the previous campaign.

Jamie Carragher advised Casemiro to retire from elite football earlier this year, and following this performance, the scrutiny will only grow more intense. It's reasonable to conclude that Manuel Ugarte, 32, has seen his days as a regular starter with Erik ten Hag numbered, especially with his arrival on deadline day.

Trent Alexander-Arnold opener denied after marginal off-side from Salah

After mistakenly believing he had scored against Manchester United, Trent Alexander-Arnold honoured the legendary Steven Gerrard of Liverpool. After United struggled to clear their spaces in the middle of the Stretford End, the Liverpool defender scored at the far post in the seventh minute. However, a touch from teammate Mohamed Salah, who appeared offside, caused VAR to promptly rule the goal out.

Alexander-Arnold wheeled away in excitement before the judgement was made, and he even planted a kiss on a TV camera, just like Steven Gerrard did several times when he scored at Old Trafford. That came after the former Reds midfielder scored goals for Liverpool in 2009, 2010 and 2014 against the same opposition during his time.